I don't know the first thing about how to mod this game, but I love where your head's at!
One of the things I find particularly frustrating in BG3 is how playing with a larger Body type locks us into a very slow moving and lumbering set of animation. The slow-mo optical illusions works for ogres, but I think it's overused. Similarly for small or tiny sized characters you get the opposite situation, where to make them seems small they had to speed up the animations there. In both cases you can have situations where a smaller creature's hitbox is being completely contained within a larger creature's hitbox, making the former near impossible to target from the main viewscreen, short of doing it via the portrait.
Also body blocks from the jumbo hitboxes are pretty frustrating for friendlies. Like trying to get around or shoot beyond allies, or a large summon or huge creature that's non-hostile is pretty challenging. In general all the hitboxes seem to take up more space than would seem to be necessary. The personal space bubble usually has a much wider radius than the actual model would appear to indicate.
Bodies of creatures that have been "knocked out" by non-lethal damage can completely obstruct certain paths, as if it were impossible to step over an Ogre who's simply knocked out rather than just dead. This does create some version of tactical depth I guess, since bodies becomes obstacles in the environment which can move around and provide some variability there, but more often than not I just find it frustrating rather than particularly challenging. When it happens to the Hostile enemies the issue is less pronounced. I mean some spells, like Wall or Fire say are pretty reliant on being able to funnel enemies around (also reliant on some pretty absurd logic from hostile NPCs, to just be all running headlong into fiery doom hehe.) But then when something like that happens to the Player, because the pathing had them walk around the giant Ogre corpse instead over it, that's like the height of annoying in BG3.
Like shouldn't it be possible to have hitboxes just turn the area into hazardous terrain when they're fallen, instead of completely obstructing that space? I mean they're bodies right, not brick walls. To me it would make sense that space became hazardous terrain such that players would have a movement malus if traversing there. Or possibly taking damage similar to an AOO or something like spike growth? Maybe the Ogre was still clutching his dagger when he went down, but made sure it was still pointing up? Whatever. That would still be better than having the space of that hitbox just totally out of play. As a player nothing is worse than having to skip a turn because you can't move, like not because someone cast hold person on you but just cause hitboxes are blocking the way forward. Jump is a bonus action in this game, but you can't use a regular action to jump on the fly, so that adds to it. There are also some summons that can't jump at all, or which are outside of our normal control and can easily get stuck bumping up against a big hitbox.
