so why did we get vita resolution screens at first
That's just how Japan manages assets, they are traditionally super-protective over image rights and display restrictions and size allowances and logo stamping, for better or worse. (The anime industry has horror stories of trying to get materials for regionalized DVDs and not receiving best-quality material while still being saddled with restrictions on the material given.) Back in the day, Japanese studios used to announce games with postage-stamp images (and never ran Famitsu magazine content online, of course), so we're lucky things have changed even if there are still wonky choices.
The game really looks like resin kits being displayed in expensive dioramas...
Yeah, we'll have to see it in motion, but I kind of like the look of it even though it's pretty far from the photorealistic realism we're shooting for these days. It feels like a game made on a last-gen engine with the developers going crazy with the extra legroom of the new console. (Tokiden on Vita was a little like this for me, I could see the PSP game underneath but they slathered it in such nice texturing and effects that it ended up being one of the best-looking Vita games; FF Type-0 HD should have been more like that than it ended up being.) Clean effects, high-resolution-but-flat textures, depth effects on some elements to give them dimension, etc. Some shots here, they work better than others, so I'm not sure what percentage of the game will compare to the better-looking shots than the worse-looking ones, but overall, it comes together for me, and I like that it looks more creatively oriented towards JRPGs from the 2000s than games today.