scotts33 I will say that over 1/3 of the over sized putter grips I have installed come off within a year after players try them.
I think something that never comes into consideration on a putter is the grip weight. A really heavy grip can drastically change how the putter feels when swinging, not just grip feel. Call it swing weight, MOI, pendulum effect, whatever, the perceived swing weight or feel can have an effect on performance usually in distance control. I started noticing this when using the super long 22" putter grips when belly putters were legal. Perhaps if people are having issues with the oversize/heavier grips a heavier putter head might be of assistance. These are just my personal observations and have no tech data to back this up. YMMV.