I feel like that would strongly resemble Greek mythology.
I'm going to have to go back and look at my 6th ed rules. I originally thought that Combat Luck didn't stack with physical armor and couldn't be bought at more than one level.
For higher-powered campaigns I'd really be inclined to redefine Combat Luck as damage reduction rather than rPD. I put up with the rPD version because it's simpler, but once your typical DCs are up in the 9-10 range, I'd rather take a percentage off. That helps prevent sudden PC death but still allows for death of 1000 cuts.
rPD in general has always been hard to balance in FH, mainly because the rPD values for different types of armor are inflexibly defined. For most of my FH experience, 8 rPD is really high, and half of the hits from 6-7 DC attacks just bounce off. In the OP's campaign, the 3.5d6K hits will do enough to bring that guy down in four hits, and possibly one.
For the OP situation, I would probably do three things:
One, redefine the typical rPD values for physical armor upwards a bit. Either because there's lots of magical armor floating around or because steel is just harder. Plate would go from 8 to 11, chain to 8, leather to 5, et cetera.
Two, likewise improve Combat Luck probably up to the 5-6 rPD range. Like I said, I'm used to Combat Luck not stacking with physical armor, but YMMV.
Three, dodge a lot.