Players bunch up and keep bumping into each other

Happens all the time in clubs; super annoying

This is a major issue I've noticed in my AI vs. AI tests. Several times a period (which only last 5 minutes) I witness an AI skater mindlessly run into another skater while neither of them have the puck and NOTHING happens. The players will continue to skate into each other at times as if the skater who was collided with is like a BRICK WALL. They don't even stumble.

Has to be addressed.

Your second paragraph is something that high level 1v1 players abuse all the time. They'll skate down the wing and predictably cut to the middle to try and shoot far-side but as they're racing down the wing, your AI players will overcommit towards them and if you try to switch to them to stop it, the AI player's previous momentum will not allow you to skate them back into position to block the shot.

Most of the time this is avoidable by playing man to man with the puck carrier but sometimes you have to switch to that d-man late and by then they're wildly out of position with their momentum going the wrong way. 

Another issue is body checking.  Let me be clear:  I'm not talking about missing an opponent by throwing a hit just as the they deke (those things happen in actual games).  I'm talking about when you try to throw a body check and your player jumps in the OPPOSITE direction from the player they were lining up.  They literally jump in the opposite direction of their momentum.  It looks like the player trying to make the hit is, instead, trying to jump out of the way.