As an umpire, your options should be limited as soon as the final out of the game is called. If you want to report it to the league, be my guest. If you want to file assault charges, hey go right ahead if you think it warrants that. But with ejecting a coach after the last out, what you're doing at that point, as I said, is essentially suspending the coach for 1 game.
I've seen football coaches do the exact same thing on game ending plays...should they be flagged 15 yards at the start of the next game? I mean, after all the refs can't become fair game at the final whistle.