That would just be silly power creep though... the other modes were buffed specifically to make them competitive with pointman - and pusher was already buffed. If you buff every single mode you make about 2 years worth of Audiosurf scores irrelevant.
Pointman pro is too weak imo, no point in using it(apart from for fun;)) since eraser and vegas will just wipe it off the boards, even below 100 traffic.
Making old scores irrelavent is no issue, if people no longer play then so what if they lose their places on scoreboard? If they still play then they should have every chance to reclaim their scores, and if their scores actually mattered to them then they would most likely welcome the competition.
Though, unfortunately, that has more or less already happened. The best solution probably would have been to bring Vegas (and eraser most likely)down to a reasonable level as compared with pointman (read: somewhat less rewarding for a somewhat less complex) but it's too late now - it's been too long for a reasonable score rollback and it would make it so that all of the ridiculous scores achieved since the last patch could never be matched.
Bringing characters down would just be rediculous since you'd have unbeatable scores on the scoreboard then.