Those vireos already looked awesome, if it's better than that then nice! But yeah thoughts like this, clearly they spent time to get that area right, but it paid off for you, and I bet it paid off for many others. Maybe not conveying perfectly but my "terrain is a main character" statement is to me that... that element of making sure each area is a character with in some sort of thought you might describe a personality, desires, faults, and an extreme importance that it is communicated for the sake of the narrative. It's obviously a narrative that isn't as clear as perhaps having a literal npc, but one I still think is important to sometimes imagine like that. The jungle in that GW2 video is amazing, how you described it is amazing, just.. "nice!".
A game, honestly a company, that I think just always "gets it" in terms of that idea is FromSoft and their Souls/Souls related sort of work. Often they have little choice but to treat the environment like a main character because they choose to not spell the story out, and so if they didn't it would just.... not work.. lol.. but clearly a series that doesn't just make an environment. I've seen a lot of neat work by FFXIV and I suspect it's not a lack of getting it but perhaps not enough allotted time or resources (engine for example almost exploded in making Khoulsia), but with that said.. I still want them to strive to make each area scream "I'm also a main character, you can't think about the story and not think about me, it's impossible". Things looking pretty obviously can help but it's not that simple, as you said you don't even think GW2 is that pretty yet that jungle still has a place in your mind due to how it interacted with you.
So.. yes, exactly, yes lol. Also those videos were pretty cool ~
Make environments main characters, always! :3