Infinite Stars
Member
If they do a legendary card of Urza the Young he'd have to be Esper so he could mirror Mishra properly. If you're really going for accuracy you could do an Esper legend that flips into a Breya planeswalker so you can include Urza's Rage.
In terms of cycles, they've hinted pretty strongly that once they go through all the obvious cycle-able color groupings they want to switch it up and do them in more thematic groupings -- like, five decks from different planes, or five decks representing five different storylines whose characters haven't been printed, or five different mechanical themes with non-cycled color profiles, or so on. Once they get into this territory I think someone like Urza becomes a lot more viable to print.
I've heard arguments that Young Urza is Jeskai and not Esper because of Urza's Rage.
I think that when they get to the point where they've done all big groups, we're going to see something like Commander for 5C Tribal, like "Hey, here's an "OOPS ALL DRAGONS" Deck that uses a bunch of cards from DTK at Common, here's a "Slivers" deck, here's a "Allies deck", here's an Elemental Deck, and here's a "Weatherlight" deck(Featuring a Weatherlight Vehicle)."