Hearthpwn

You can actually replace ysera with Nefarian or Alexstrasza. But Reno is not playable without Raza, and Chillmaw is also not really a card that you could replace, since it's a taunt and aoe in one.

You are right, Chillmaw is much harder to replace than Ysera, because Chillmaw got the Removal. I like Ysera, because there is a chance it gives you Removal too - deal 5 dmg to everyone. But what you are saying about Raza, i don't agree with that. Sure, It is a good card, i like being able to heal every turn for 0 mana, but Reno works fine without that card in the other Reno decks (Mage and Warlock). If you dont have it, or want to change it, Entomb is a pretty good solution. Just take one of their Deathrattles with Entomb, so they get One less deathrattle, and you get One more (or you can take their Raza if you are playing against Control Priest). :) 

And the card i actually like the most that Ysera gives, is Dream. More Youthfull Brewmasters is allways good, and you can play it the same turn that you play your N'zoth :) 

Is there room for Justicar Trueheart in this deck?

I would like to play the card in the deck too, but there isn't room for any more high-cost cards in this, unless you remove other high-cost cards as well. If i would put Justicar Trueheart in this deck, i would take out the Book Wyrm. But then you would need more removal, maybe Potion Of Madness, instead of Antique Healbot or Raza The Chained. :)

I spent all of my 5200 dust to complete this deck and I don't regret it.

Very fun and powerfull, it feels like every game is winnable and that you only lose to bad decisions of yours.

I still have to face very smork decks though

I came up with a name for it : dragoren'zoth

Thanks man, I'm glad that you like and enjoy the deck :D

Good idea with the Piloted Shredder :) It is better for the board control, but i like Shifting Shade better, because it is able to give you another deathrattle / dragon (or even a Piloted Shredder). 
Twilight Drake is a good card for the deck as well - always good with more dragons :) 

I'd love to know how the hell you got around all the pirates with this deck... I played 30 games with the deck so far and you litteraly have to draw almost perfect going up agianst pirates or shaman aggro. If you don't draw shadow word pain, wyrmrest, Twilight whelp, doomsayer, deathlord within the first 4 turns its usually auto loose.... You resort to praying for that Reno top deck... Why don't you run the 1 mana take control potion? 

Also out of curiosity, why no ex evil, holy nova, kabal talonpriest? Entomb? Priest of the feast? 

Against the Pirates, your comboes later doesnt matter - if you just survive, u win :) so you can play Kazakus as well on turn 4, not with Brann on turn 7 or later, against the Shaman and warriors. Against the Pirates, Mulligan for the taunts, Doomsayer, Acidic, Northshire Cleric, Twilight Whelp, Shadow Word Pain, And of course Reno Jackson.

The reason that Im not running the spells that you ask for, Entomb, Holy Nova, and Excavated Evil is, that there are better cards against the control decks out there in Wild than in Standard. I got them in my standard priest deck, but not in the Wild deck - the lightbomb is put in this deck instead of holy nova/excavated evil, and as much as i like entomb myself - we allready got enough Deathrattles + Dragons in the deck. And Entomb won't help against the pirates, nor Jaraxus :) And Kabal Talonpriest doesn't fit well in a Reno Priest deck, it is much better in a mid game dragon Priest deck :) 

I can give you some hint's on some good priest cards, that could replace them - but if you take out Chillmaw and Ysera, the Deck would not be able to be played as a dragon deck anymore, unless it's 2 other dragons you put in. 
I Would put in Nefarian and Chromaggus instead of the 2 dragons Ysera and Chillmaw. And then take Raza out, and put some kind of removal in the deck (cuz chillmaw removes, and is a deathrattle for N'zoth). I would put in an Entomb so you can take 1 of their deathrattles, or Holy Nova/Excavated Evil if you prefer them. :)