I love that idea. Then they could also bring back the original point system (9, 6, 3, 1 for 1st, 2nd, 3rd, and 4th respectively). Then they could also do like in MKDD and MKW: Only X number of characters per GP, but they are random/rotate out, and on a similar note: Similar characters (Mario and Baby Mario, Luigi and Baby Luigi, etc*) don't appear in the same GP run (unless the player happens to be playing as one).
* If that's confusing: Mario and Luigi can appear in the same GP, but if Mario appears, Baby Mario won't. I don't want to race against six forms of Mario