Hearthpwn

All is in the title.

For me it would be Toki, Time-Tinker and Whizbang the Wonderful.

Dragon queen Alex would be cool if Reno stays. (Not really interested in seeing Zeph again though.)

I'll nominate Earthquake. With Reborn becoming a core mechanic, there's a sore lack of removal which can deal with sticky minions. Earthquake would serve a solid role as a board clear which can deal with Deatrattle tokens and Reborns.

Can I vote "Not Brann Bronzebeard"? I'm still baffled that they not only put him in Standard this year, but LEFT him in there, when time and time again he was part of the reason for brand new cards to have to be nerfed.

I'd love to see death knight hero cards from frozen throne. some even buffed.

Mind Control Tech

Mass Resurrection and Hysteria

druid needs spreading plague to be relevant again

Hunters will lose a lot of draw options in the rotation; it would be pretty fun to see Starving Buzzard in Core.  Hunters will also lose Ice Trap, so a replacement secret would be welcome; maybe Wandering Monster.  Bola Shot or Grievous Bite, and Wing Blast or Overwhelm.  Stitched Tracker.  Maybe Vereesa Windrunner, to try to push the Arcane archetype.

N'Zoth, the Corruptor

Will probably be quite useless because lol, turn 10 in modern hearthstone but I'd love to see this boy back.

Neptulon but buffed to 5 or even 4 mana

Defile