I had a certain amount of success using rolemaster for 40k in the past, however it suffered from a "sameness" of enemies and a lack of tactical complexity.
So my goal would be to add a bit of tactical variation to Rolemaster without burdening the rules. Some weapons are going to bounce off armour, others are going to penetrate it, some are going to do immediate damage, others are simply going to slow or encumber their target. In some ways the critical system with it's bleeds, stuns and on-going penalties is good.
What I'm not so sure about is the "it always hits" aspect of the charts. I think the spread is too large, I would prefer charts with a narrower band of success, perhaps using damage multipliers rather than adding bonuses to charts. I think the mechanics of the system are such that +15 material bonus is the most that can be used before serious change to the distribution occurs. This actually has good synergy with 40k- decrepit or poorly manufactured gear should have minuses, higher breakage numbers etc. High bonus gear should be really rare in 40k
