I think this is one thing that people have been glossing over significantly. TTK aside, nothing feels like it did in D1. Your shots hit, you felt on target, and YOU COULDN'T BLOCK OR GET BLOCKED BY A TEAMMATE SO DAMN EASILY. It feels bulkier, and not just in the speed sense. It feels bulkier in the "amount of room I take up" sense.
Reduced aim-assist. ..and the ability of team mates to knock you aside is annoying in both PVP and PVE. I don't know how many times I've died in strikes because of randoms that clumsily knocked me out of cover while I was trying to get my health back.