In no particular order:
I want to produce decks that are very synergistic, closer to constructed decks than typical cube decks.
I want to explore an abundance of fetches/fixing with wastelands to keep things in check.
I want deck to have interesting sideboarding decisions.
I want to use the breaking of singleton to essentially only run cards which are very interesting (go in many places, make for interesting buildarounds) DRC is the posterchild for this
I want colors to have quite a bit of access to the effects which are core to their identity - at a good rate. E.g. black should have plenty of discard spells

Some other design decisions:
I want archangel of thune to be playable in a fair-ish way. This means mostly giving black removal that can't kill it. In particular I'm leveraging the restriction on power word kill. This means that I don't want to run the generically good dragons in the red 5-drop slot.

Creature selection has been done with birthing pod in mind, trying to give every non-blue color a good pod target at each cmc (and blue some too)

Some archetyes I hope are currently supported (some not all that distinct):
UW blink (ephemerate, kitten, watcher, wall of omens)
UW miracles (brainstorm, terminus)
WB tokens (staff of the storyteller, bitterblossom)
WR artifacts aggro (esper sentinel, galvanic blast)
WR kikki (resto angel + kikki)
WG creature combos (heliod+ballista/spike feeder, archangel of thune + spike feeder, heliod+kitchen finks + sac outlet, devoted druid swift reconfiguration)
UB faeries (Bitterblossom + spellstutter sprite)
UR spells (iconoclast, dreahorde arcanist)
UR artifatcs (Urza, iconoclast)
UG Hermit druid combo (thassa's oracle, hermit druid)
BR aristocrats (entomb, gravecrawler, carrion feeder, goblin bombardment, poxwalkers)
BR welder (goblin welder, necron deathmark)
BG midrange (thoughtseize, tarmogoyf)
GR delerium midrange (DRC, tarmogoyf)
GR lands midrange (wasteland, life from the loam, titania)
GR discard (Inti, life from the loam, faithless lotting, currency converter)
Various pod decks e.g. all in kikki (e.g. 1->corridor monitor -> renegade rallier -> resto -> kikki)
Various graveyard decks (vengevine, hoogak, faithless looting, stitcher's supplier)

Things that I would in principle like to support but haven't figured out a good way of doing/suspect aren't supported enough:
UWR control
WB aristocrats
Various other midrange decks
Domain