The kick function is essentially a double-edged sword. It grants the host the ability to remove unwanted annoyances from the lobby, but at the same time it sucks to be the guy in a person's lobby that kicks without rhyme or reason. The best solution is to move on and play more reasonable people, or simply make your own lobby.
The Online Dojo is fine. I see no reason why it should be removed, especially to practice combos and setups among friends (such as co-op tag). It's especially useful for those who don't readily have or have difficulty building an offline scene.
Online Dojo is great. I meant removing the Dojo stage from normal play. Dojo completely removes the wall game which is an important aspect of the game, I think.