I suggest polestagger to be entirely removed from all polearms with more attack directions than 1. It's really not needed on weapons that are equivalent if not better than 2h on many aspects without it.
However, some of the longest (read, less efficient as non-support weapons) 2-directional polearms should keep it, like the lances, long awlpike, bamboo spear, swiss halberd and english bill...
And certainly the pike and long spear should keep it. Those are already underused weapons. Removing the stagger would defeat their support purpose.