markc, i did ask a similar question a while back in the revision (specifically we discussed the number of stats). It's archived now, but I thought I'd run a poll about it.
Also though, keep in mind with RM2 you can still use 3 stats (and 3 stats are used for melee for instance), it just means averaging them. This question isn't so much about the # of stats as the method - either use a variable number of stats with averaging (RMC), or a fixed number of stats with an additive method (RMFRP).