a lot has been said here that i really agree with! as an environment artist, i am obsessed with background detail - it's one factor in why i love PLA - and although there's something cooking there, i agree that it feels really empty.
actually, maybe my issue is more about how the game looks from afar. in addition to having a tacky visible tiled texture on distant terrain (looks better up close, but bad when it's just a stretch of land with nothing on it), i'm not a huge fan of... i don't know. the color grading? the shading? it's so hard to figure out the exact point of contention. the colors are washed-out and feel dull in some places, like the southwestern fields.
THAT SAID. aside from glitches and the above things... i do enjoy wandering around, and i love the city designs. you can tell they were kind of stretched thin and couldn't make interiors for npc houses with whatever deadline they had, which does hurt it some, but i really adore the general layouts of most of the towns. they're all so distinct and i really enjoy how varied they are.
i think it really does suffer from the pitfall of open world design, though. if they had more large obstacles to block view, they could have managed performance better, i think. and also, it was kind of annoying to keep running into a super tiny flabebe when i'm trying to go somewhere specific. maybe i'm just a hater? but i really wished more of the towns had more "cover". i would often appear at a town and go, wow, it's kind of just smack dab in the middle of the field, huh? and you can see for miles... it just felt... i don't know. undercooked, underbaked...
that said, i haven't tried or purchased the DLC. i really dislike the trend that gaming has formed where the REAL MEAT OF A GAME is locked behind a second paywall. especially when that DLC is around the same price as when i went to buy pokemon pearl NEW, over a decade ago.
the pokemon designs are fun though. i love clodsire and appletun so so so so so so much. dudunsparce was, in my opinion, the best design concept for such a pokemon. dunsparce, but more. i don't find it lazy - i find it incredibly fitting and cute that it isn't overdesigned and doesn't stray too hard from the first stage. it's great.