Apologies in advance, I'm known to ramble.
In 5e, medium creatures control a 5ft cube around them. Clearly they're not actually 5x5x5 ft, but they can choose who is and isn't allowed to move through that space. In BG3, this area is much smaller, roughly the size of the creature themselves. This makes it really tough to properly block off a chokepoint with your frontline. You need two people to block off a single doorway, while in PnP this is usually doable by only one character. Please increase the space that an ally controls so enemies can't just slip in between my fighter and my cleric to kick my wizard's teeth in.