1. Vote Kick. It's pretty annoying when the party leader gets disconnected and you end up stuck on a floor. To my knowledge the only options when this happens are to go solo or go back to the haven.
2. IMO, enemy knock-back needs to be decreased or eliminated on non-final swings. I find myself & everyone else trapping enemies in corners or against walls in order to do anything, which is silly. This is especially a problem when using my dread venom, as enemies are often only hit on every other attack, making it's awesome 5 (10) hit combo, well, not so awesome.
I have an issue with your second suggestion. I have a feeling you haven't explored T3 just yet, so you don't realize the importance of that knock-back. What it does is allow players to poke groups of enemies for damage while still remaining at a safe range from a counter-attack. When T3 has enemies that will take off around 4-5 bars minimum at a time, you definitely want that knockback otherwise you're getting swarmed.