Congratulations, you get to be Sirrian's gatekeeper where you get to ask him the especially interesting questions, then get back to us
Unity I'm hoping will allow easy dynamic text in cards. So queen mab have the 13 flash when there are enough blue gems for an extra turn is easy. But I think Sirrian has bigger reasons for wanting dynamic text.
Non-linear troop buffs, something that would require dynamic text. Long requested but previously not possible.
All knights gain 2 life. At some point, increase to 3,4, or 5. Or give an armor, attack or magic boost.
Burn damage normally does three. Can be boosted.
Gem creation based on magic, at some point it takes more than one magic to create one additional gem.
All boost values could custom scale like mana power to mana surge % does. Bone dragon finally properly balanced, good at low level but not ridiculous at end game.