OK; so now that I've done more Arenas; I'll quickly say what I've seen and experienced with every class.
Druid - I have literally not seen any Druids in Arena since C+C besides the one I played. I had a good Druid run yesterday myself; which went 7-3. The losses were because I was a Big Druid; and 2 of them I just got Faced down; and the third was a Rouge who played 3 different Poisonous minions; Sap; Onyx; and Assassinate in the first half of their deck, so was basically made to be Anti-Big Druid. Also this Druid deck had no ramp; no AoE buffs and no Swipes; things that usually define Druid. It was just... top-heavy Druid.
Hunter - I have been seeing a surprising amount of Hunters [22%]. A lot of them are using quite a few secrets and their Spellstone; but this is pretty inconsistent in Arena. I have also beaten almost every Hunter I've faced, the only losses being with Rouge [Who in general has a pretty bad Hunter matchup and I can never seem to get even a passable draft for] and Druid [Which was a slow deck which got SMOrc'ed].
I played Hunter and went 6-3; although most of my losses were me topdecking too many of my weapons [I had 4 in the deck]; so simply not being able to keep up board presence. Also I had no Houndmasters; and lost in a HuntervHunter topdeck war because the other Hunter went Call of the Wild -> Highmane.
Mage - Has the offering rate for Mage gone down? Because I'm only seeing Mages 11% of the time; and I've only got to play as Mage once before I remembered to track my stats. Said Mage was an 8-3 run however; my equal best so far in C+C. Mage is still very powerful. As long as they have such powerful removal and burn options combined; and such high-quality commons; they will be powerful.
Paladin - I have also hardly seen any Paladins. I've been against them in 8% of my games; with a 2/3 winrate against them. None of the Paladin decks I faced I could call particularly good either [The Paladin deck that beat me was the ill-fated Rouge draft I had]. That said; I did have a Paladin draft which went 8-3. This was a pretty aggressive Paladin deck. Priests were the majority of my losses on this run; usually because they would copy the exact card they needed from my deck; such as my 1 copy of Consecration. That said; this deck also beat Priests.
Unidentified Maul is a really good Arena card by the way. Especially when a Paladin deck that already leans aggressively. How aggressive was this Pally? It faced 2 Hunters. One conceded Turn 5. The other got Turn 7 Leathal'ed. Face is indeed the place.
Priest - I'm seeing Priests everywhere and they are the majority of my losses. That said; the majority of the time; it's not really because of the Priest's down deck. Sometimes it's this insane Priest deck that fairly shuts off my Hunter/Paladin deck with just infinite healing. But most of the time it's a case of 'Lol I Devour Minded your best cards'.
I think what makes Priest so strong right now is actually the amount of card advantage they can accrue... from your deck. Between cards like Shifting Shade; Crystalline Oracle; Thoughtsteal and Devour Mind... Priests just don't run out of cards, and seem to keep getting your best ones. Most of my Priest losses have left me feeling cheated. Not even Mages usually make me feel like that. There's also the fact that Free from Amber is just stupid.
I haven't actually got around to trying Priest myself in C+C.
Rogue - Whenever I draft Rouge; I get literal hot garbage and never draw the thing I need; as in; 0-3 is the most common result on Rogue for me and I actively avoid drafting it. Whenever I face a Rogue; they seem tailor-made to beat my deck. [See: The Druid loss to Rogue]. They also have a bit of Priest syndrome where their random cards from your class will be exactly what they need. Rogue is certainly weaker now however. C+C diluted their card pool quite a bit. Particularly with the Secrets.
Shaman - Seems to be in a bad spot. I had what I thought was a powerful Shaman deck [2 4 mana 7/7's. A decent chunk of Jade; some removal; Prince Malchezarr] and I only went 5-3. Another Shaman deck which I was significantly less confident in went 1-3. In addition; I've not lost to a Shaman yet either.
Warlock - I haven't drafted a Warlock yet; but I'm seeing them everywhere. The reason for this is beyond me. Warlock is my 3rd most commonly encountered class [Just behind Priests and Hunters] and yet I have only lost to Warlocks twice; both with decks that didn't even manage 2 wins. Is it because the Warlock players are bad? Or is it because Arena Warlock is still bad? I won't know until I draft a Warlock... but Warlock has always been my 2nd lowest rank to draft... so I'd have to pick Warlock over a class I think is stronger.
Warrior - Extinct. I encountered 1; and steamrolled it.
IMO:
Priest/Mage/Paladin [Priest may be top] > Rogue/Druid/Hunter > Warlock > Shaman > Warrior
OK; so now that I've done more Arenas; I'll quickly say what I've seen and experienced with every class.
Druid - I have literally not seen any Druids in Arena since C+C besides the one I played. I had a good Druid run yesterday myself; which went 7-3. The losses were because I was a Big Druid; and 2 of them I just got Faced down; and the third was a Rouge who played 3 different Poisonous minions; Sap; Onyx; and Assassinate in the first half of their deck, so was basically made to be Anti-Big Druid. Also this Druid deck had no ramp; no AoE buffs and no Swipes; things that usually define Druid. It was just... top-heavy Druid.
Hunter - I have been seeing a surprising amount of Hunters [22%]. A lot of them are using quite a few secrets and their Spellstone; but this is pretty inconsistent in Arena. I have also beaten almost every Hunter I've faced, the only losses being with Rouge [Who in general has a pretty bad Hunter matchup and I can never seem to get even a passable draft for] and Druid [Which was a slow deck which got SMOrc'ed].
I played Hunter and went 6-3; although most of my losses were me topdecking too many of my weapons [I had 4 in the deck]; so simply not being able to keep up board presence. Also I had no Houndmasters; and lost in a HuntervHunter topdeck war because the other Hunter went Call of the Wild -> Highmane.
Mage - Has the offering rate for Mage gone down? Because I'm only seeing Mages 11% of the time; and I've only got to play as Mage once before I remembered to track my stats. Said Mage was an 8-3 run however; my equal best so far in C+C. Mage is still very powerful. As long as they have such powerful removal and burn options combined; and such high-quality commons; they will be powerful.
Paladin - I have also hardly seen any Paladins. I've been against them in 8% of my games; with a 2/3 winrate against them. None of the Paladin decks I faced I could call particularly good either [The Paladin deck that beat me was the ill-fated Rouge draft I had]. That said; I did have a Paladin draft which went 8-3. This was a pretty aggressive Paladin deck. Priests were the majority of my losses on this run; usually because they would copy the exact card they needed from my deck; such as my 1 copy of Consecration. That said; this deck also beat Priests.
Unidentified Maul is a really good Arena card by the way. Especially when a Paladin deck that already leans aggressively. How aggressive was this Pally? It faced 2 Hunters. One conceded Turn 5. The other got Turn 7 Leathal'ed. Face is indeed the place.
Priest - I'm seeing Priests everywhere and they are the majority of my losses. That said; the majority of the time; it's not really because of the Priest's down deck. Sometimes it's this insane Priest deck that fairly shuts off my Hunter/Paladin deck with just infinite healing. But most of the time it's a case of 'Lol I Devour Minded your best cards'.
I think what makes Priest so strong right now is actually the amount of card advantage they can accrue... from your deck. Between cards like Shifting Shade; Crystalline Oracle; Thoughtsteal and Devour Mind... Priests just don't run out of cards, and seem to keep getting your best ones. Most of my Priest losses have left me feeling cheated. Not even Mages usually make me feel like that. There's also the fact that Free from Amber is just stupid.
I haven't actually got around to trying Priest myself in C+C.
Rogue - Whenever I draft Rouge; I get literal hot garbage and never draw the thing I need; as in; 0-3 is the most common result on Rogue for me and I actively avoid drafting it. Whenever I face a Rogue; they seem tailor-made to beat my deck. [See: The Druid loss to Rogue]. They also have a bit of Priest syndrome where their random cards from your class will be exactly what they need. Rogue is certainly weaker now however. C+C diluted their card pool quite a bit. Particularly with the Secrets.
Shaman - Seems to be in a bad spot. I had what I thought was a powerful Shaman deck [2 4 mana 7/7's. A decent chunk of Jade; some removal; Prince Malchezarr] and I only went 5-3. Another Shaman deck which I was significantly less confident in went 1-3. In addition; I've not lost to a Shaman yet either.
Warlock - I haven't drafted a Warlock yet; but I'm seeing them everywhere. The reason for this is beyond me. Warlock is my 3rd most commonly encountered class [Just behind Priests and Hunters] and yet I have only lost to Warlocks twice; both with decks that didn't even manage 2 wins. Is it because the Warlock players are bad? Or is it because Arena Warlock is still bad? I won't know until I draft a Warlock... but Warlock has always been my 2nd lowest rank to draft... so I'd have to pick Warlock over a class I think is stronger.
Warrior - Extinct. I encountered 1; and steamrolled it.
IMO:
Priest/Mage/Paladin [Priest may be top] > Rogue/Druid/Hunter > Warlock > Shaman > Warrior
Current Deck -http://www.hearthpwn.com/decks/240420-army-paladin - Token Paladin
I'm seeing a strangely high amount of Warlocks. They're basically free wins for my Mage run right now.
Seeing a lot of the 4/10 Ettin; which is annoying.
Current Deck -http://www.hearthpwn.com/decks/240420-army-paladin - Token Paladin