Been trying to mess around with the priest and I feel like i've come up with a pretty good deck although it feels like it's missing something or theres a lack of synergy with the cards? Maybe I've got too many focuses eg - drawing, healing/buffing, board control etc?
If the focus is to make a draw deck, Illidan should be one of the main power cards in the deck, granting you extra power for all the cards you accumulated. For a draw focused deck I'd say that you don't have enough draw power.
My recommended changes would be.
*To gain more draw power you should certainly add another Northshire Cleric. Swapping Mindgames for Thoughtsteal could also be a good way to get more cards to play. With enough draw power you could remove one of the copies of Mind Control as you will often have it in hand with so many card's drawn.
*Ysera would have a lot better synergy than Malygos as spell power does not affect healing. While having same stats as Malygos for the Divine Spirit+Inner Fire combo she also gives you an extra card to play every turn to feed Illidan .
*With many cards to play, the Questing Adventurer would be a great card to have. Consider if you could fit him somewhere.
not about the deck, but I'd like to add a little something to share.
During our playtests, it happened that adding too much draw power to a deck led to a deck being quickly empty and hands fulls of cards you can't play just because of the 10 mana limit. As there are no real sure way to win a game yet with a full hand of cards (Warsong Commander, 2x Molten Giants, Brewmaster = lol), my conclusion was to decrease the draw power of many of my decks. That said, drawing in a card game is always awesome and I'm having a had time finding a satisfying balance.
i was curious if anyone came to any conclusion regarding this specific point.
While I ain't playtesting, I find it a valid concern. While having your deck in your hand always grants you more options. Not being able to get them out on the field when necessary removes a lot of the power of having the card's in hand. I believe that the balance in draw power should be weighed against the mana cost of the cards in the deck. I figure that most of the cards in the deck should be at 3-2 mana cost with some situational high cost cards at the top (pref 5-7 mana).
However, a deck based around playing cards and one that draw cards to find the cards they want is different. For example there are many cards that allows you to play more cards. That includes Mind Vision that for one card, you get 2 cards to play. Other cards available for the priest are Thoughtsteal, bounce cards (Youthful Brewmaster), Ysera and Lorewalker Cho. Together with cheap cards, these cards allow you to decrease your draw power while still having a lot of playing power.
I think both of you nailed it: the limiting factor of a Priest deck is not card advantage, it's tempo. You get swarmed by cheap threats before you can play your cards and win.
Another common mistake of players who haven't play tested yet is to see the potential of each card if it would stay on the table for several turns. Cards like Gadgetzan Auctioneer or Illidan Stormrage need to be acted on immediately, because it is very likely you won't start your next turn with them. If it happens, great, you insta-win. I mean, give me 6 mana and a hand full of spells with an Auctioneer on the table, and yes, I've pretty much won. But it doesn't happen. Every good deck handled by a good player will have a (top of my head) 70% per cent chance to kill your Illidan in a turn, 2 if you're lucky.
This is why Mind Control is silly good, even at 8 mana. It's because as a priest you're constantly behind the tempo of your opponent... And if you manage to deal with everything, once you hit those 8 mana, Mind control solves the latest threat and puts you ahead because you now own it. If instead of mind control you do, say, Ysera, you run the high risk that your opponent just ignores it and mashes your face to death, since it's not even a taunter. I've lost many games like that, thinking "now I've got board control, if I can last just one more turn I got this"... but you almost never do.
Looking at your deck, I think you can do without Mass Dispell. It's not a bad card, it's just too situational to deserve a spot. You'll lose a turn doing it, for a card and no real solution to what you face. Velen is meh in your deck as well, it only boosts holy nova, and you'll have those cast way before you can put him out. Malygos is pretty bad synergy too, as pointed out.
I'd replace those with 2 Acidic Swamp Ooze and Harrison Jones to cheapen the deck, deal with weapons (which is key against 3, maybe 4 classes) and have more early solutions (a turn 2 ooze against a non-weapon deck) is basically 3 damage to a minion.
Acolyte of Pain and Northshire Cleric are all the draw you need in a priest deck you can buff their health if you want and use several aoe or single heals to trigger their effects multple times. I would suggest Darkscale Healer for this purpose.