I seem to recall that earlier editions of Rolemaster did a couple things I liked, which were unfortunately later simplified:
1. Critical progression wasn't always linear. Sometimes a 134 was better than a 135. Not often, but little variances add some spice.
2. The critical types weren't the same. Broadswords tended to do Impact, and then Krush criticals against heavier armor types, before finally getting to Slash.
I think a combination of these, and going back to single-step progression (i.e. 130, 131, 132 instead of 130-131, 132-133, etc.) could add some interesting variation. Imagine if you went AI, BI, CI, AK, BK, CK, AS, AP, BP, CP, DP, EP.
Above all, though: pull the implied quickness penalty out of the tables, and allow the Armor's Qu penalty to push the Qu DB negative.