Rogue: give rogue discard tools. Would help slow the meta down a bit. Nothing too early, maybe starting at 3 cost.
Druid: support celestial allignment. Seems like a cool and novel way to play. Give it a little more love.
Priest: Give more control tools. My idea, "cost 8 spell. Switch boards then destroy all friendly minions" has downside from twisting nether that any minions on you side go to opponent. Upside in that you get opponents deathrattles and steal any dormant minions.
Hunter: Id give them an overstatted vanilla minion with agressive statline or two. Like a 7/3 for 3. Must be dealt with asap, but can be killed before doing damage.
Warlock: just some actually good demons.
Paladin: maybe some weapon support. "For the rest of the game your weapons have lifesteal" sort of support. Maybe weapons that give future weapons more juice.
Warrior: more bombs. But maybe more varied bombs? Maybe they destroy a random minion or mana crystal or card in deck. Just something other than face damage.
Shaman: maybe just some good old murlock support.
Dh: more deathrattle support.
Mage: maybe something to leverage deathrattles. Something like shudderwock for deathrattles?
I can't say I agree with you on most of these... I can feel some trolls ready to jump in here and curse you. I'll be nice, though. At least you're trying to be constructive!
Personally, I'd really like to see some big spell support from mage.
We just got Celestial Ink Set and Clumsy Courier. This just stinks of big spells, but what big spells can we really make use of right now? Biggest spell is 8 cost and only works if you're playing elementals. Not even sure if the courier can activate the secondary effect...
I know people are going to hate on me for saying this, but I kinda miss Puzzle Box of Yogg-Saron. It was nothing else but interesting. Sometimes good. That's the kind of card I want to see Clumsy Courier "drop" on the board. :)
Celestial Alignment is already quite strong honesty on its own, it just needs a slightly slower meta to be just absurdly busted. Moreover, I think it's a really frustrating card to play against, especially because Druid can cheat the 1 mana cost into a 0 cost with Lady Anaconda or other shenanigans.
Appart from that, I don't really like your suggestions as it seems to support what I consider frustrating archetypes, but it's just my bias personal preferences. As a control/wacky decks lover, I would love to see some hero cards (maybe some early ones, with less impactful hero power), and also more support for each tribes (murloc, mech, pirates, ect...). I would like also a way to slow down questlines but I can't find anything that is smart and not just a vanilla tech card.