How to improve triple FD performance?

it's my wife's Marin Fairfax Alp, with entry level 3x8 flat bar shifting, and road gearing. The original left shifter had already exploded, so I replaced both shifters with a set of Shimano ST-R225's. The FD is an R-334, and the crank is an optimistic 52-42-30. It takes about two fingers of slack in the first position of the little ring, just to make to the big ring. Even so, with the inner guide laying against the seat tube, the chain still rubs in little-little.

I could swap out the front mechanics with SRAM twisters, and suitable FD. (Or will SRAM shifters pull Shimano deraileurs?) But then why not do the rear mech's to match? Or go to XT, although I'm not sure there is a mountain ratio FD that would handle 52 teeth. Not that my wife ever goes that fast. So why not go with a compact double? But then she would need a bigger cog for hills...

You see where this is going....

thanks for reading ;-)