Brainstorming a setting for a Tier 4 classes only game

[Troacctid]

That's a fair point. I'd imagine that would knock down Psychic Rogue a bit; would that empower mid-level casters like the Hexblade or misc buffers like the Dragon Shaman enough to be considered T4 in this setting though? I haven't played either of the latter, but I'd imagine the Dragon Shaman healing utility would be more pronounced in a world without NI wands of cure light wounds to purchase...

Adepts are right there. They can do crafting just fine. In fact, I wouldn't be surprised if Craft Wand were a common feat for them, since they have so few spell slots. Same with the half-casters.

Psychic rogue's power isn't really dependent on UPD, so I wouldn't expect it to lose much power. However, if your campaign takes place at lower levels (say levels 1–10), a lot of classes might move around because of that.

I think NPC classes want to still be around for gameplay reasons. They are legitimately useful for building NPCs.