Hearthpwn

Always mulligan for your early game minions. Removal spells aren't as important, you want to control the board with your minions first and after they trade for board and you start getting outvalued by minions then you want to start drawing into your board clears.  Squeeze in your lifetaps whenever possible. If you don't have the answers to their cards it means you weren't drawing enough. The natural card-draw of the Warlock class does wonders to keep your hand full and give you answers and threats to everything. Finally, don't be afraid to Reno early. Healing for 14 feels really weak but sometimes playing an early Reno to play around your opponents outs and to also develop the board is more important than playing greedy and trying to heal for 20+

Last but not least, keep playing the deck. As you invest more time, you'll notice synergies, cards that are a keep in the mulligan against certain matchups, etc. The only way to improve your play is to take an introspective look at your games afterwards and always be looking to see what you could do better.

renolock is currently weak thanks to this hunter heavy meta. although renolock is sick in tourneys so.

2-12 on EU. 

Any ideas for Ragnaros replacement?

Can I replace  Alexstrasza with Lord Jaraxxus?

Yes. For laddering purposes Lord Jaraxxus is better than Alexstrasza because he gives you a win condition against Control decks. Alex is purely run for the tournament to facilitate the 20 damage Leeroy Jenkins + Power Overwhelming + Faceless Manipulator burst combo as the primary win condition. If you do so, I would also recommend swapping out the single Soulfire which is used for extra reach with the burst combo for a Sunfury Protector to synergize with the Infernals that Lord Jaraxxus will spawn and to give yourself more taunt walls to stall the midgame to guarentee you win in the lategame.

Thank you!

Would it be feasible to substitute blood mage thalnos for swamp ooze?

The deck is great just had a 5-0 run on the ladder, defeating 2 Midrange Hunter, 1 Midrange Shaman, 1 Grim Patron and 1 Tempo Warrior: Featuring 3 of the games in this video

The most obvious change since the last tournament where he used the renolock is the use of Alexstrasza instead of Lord Jaraxxus. He also switch the mind control tech with the cult apothecary.

Hope that helps, if you are wondering what he was using prior.

What would I be able to replace Sylvanas Windrunner with?

Maybe a Mind Control Tech

Sylvanas Windrunner is very difficult to replace given her strength in control style decks. I would strongly recommend crafting her as she is a staple legendary used in practically every midrange/control deck in the meta for the moment. She has so much synergy with Shadowflame and Power Overwhelming as well as represents a formidable obstacle on an empty board to an opponent's Ragnaros the Firelord or C'Thun. Your best bet to replace her with is another strong mid/lategame minion like Azure Drake or a Dread Infernal but these are extremely weak substitutes.

can i play this deck without alex? I have been using jaraxxus instead 

Yup. Lord Jaraxxus will increase your winrate against control decks that don't pack any burst reach like Blood To Ichor + Grommash Hellscream or that lack board clears like Priest/Druid. Alexstrasza is purely used to facilitate the 20 burst damage combo this deck is built for in the tournament. Not many people were running hyper control decks therefore Lord Jaraxxus would have been to slow.

Because harrison gets played alot. Jarraxxus can be a liability.

I dont think thats a huge downside, Jaraxxus gets played VERY late. In that state of the game it might be even better if your opponent draws so many cards because it will probably fatigue him instantly or very very soon at least.

I still understand that he isnt in the Deck. There arent that many Control Decks in Tournaments right now, the only match-ups where Jaraxxus can be useful (in this one) are control warrior and Nzoth paladin, which is only every 8th Deck in the Tournament.

Looks like it turned out pretty well

I think that's because your win condition is the leeroy's combo. If you jaraxxus you will be able to draw less and you will have less changes of drawing the combo..