Given that wrc+ is a summary statistic I really doubt it had made Votto a better player. My guess, as has been mentioned by others here is that he probably uses it as a good measure of his performance if he had to look at one stat. Actually looking at ones wrc+ offers very little chances to improve as all the factors are packed in, and thus it would probably be more instructive to look at the make-up of it to improve, and I wonder if Votto does that.
As far as Jpa goes, it's hard to believe that using wrc+ would help him any as looking at the formula, hrs are more valued than walks ( it doesn't take into account, AFAIK the 'availability' of each, and someone of jpas mental stature may simply think he needs more hrs!
This thread, however is quite dumb as the main posters are attempting to indirectly cite jpas ( one of the worst players) struggles as his rejection of saber stats and Votto ( one if the best) as his acceptance.
It would seem much more logical to me that their difference is actually that Votto is good because he's talented and Jpa is bad because he's not. I can't suspect, to any significant level either of their wrcs would change if they looked at other stats. ( real question is: can Jpa even take walks??)
But it's nice to see this forum still trying to win the $/war crown