One of the problems in higher level play in 4E is that player abilities can “stun-lock” a monster such that it can take no (or limited) actions for a series of turns. This can create an anti-climatic fight for the end of an adventure. One thing I have started to do (past Heroic Tier) is to allow a monster’s use of an Action Point to end all ongoing/save effects currently affecting it. Of course, such use of the monster’s Action Point means it uses that Action Point only to end the ongoing effect and it does not gain an extra action.
It is only Elite and Solo monsters that have Action Points, so it will only be the “hard” or adventure threatening monsters that can do such a thing. This is in keeping with these types of monsters being high points of an adventure.