UEFA waiting until after the competition is over isn't necessarily a bad thing. If the police find evidence that this was a planned ambush of the Manchester City coach and there was premeditated thoughts to vandalise the bus (shouldn't be too hard to find, just check twitter) the RS could be looking at a stadium ban next season.
This also means that Liverpool fans have to be on their absolute best behaviour for the remainder of this competition. Any repeat behaviour of their fans in the semis home leg or if their fans go abroad to Spain, Germany or the final in Kyiv and smash the place up then the club will be in very serious trouble. UEFA tend to stack up charges when dealing with a club.
And the good thing about this is their fans are the absolute scum of the earth, they'll almost certainly get in trouble one way or another.
Was thinking that myself because, if they got punished now imagine the cries of "UEFA are only doing it because they don't want us to win it etc, etc"