I certainly see your point, though for me, personally, what I perceive to be the mission of Wikipedia, is much more important than any individual. I don't need to see a face to understand that Wikipedia is important -- I need only look at my browser history or the number of times Wikipedia is quoted as a source. What I need to know is how much Wikipedia needs (on an ongoing basis) and for what. And I need it to be presented plainly.
I have donated to Wikipedia in the past -- even before Wikipedia was a household name (which isn't something I say to seem like some hipster schmuck, but to illustrate that I believe enough in what Wikipedia does to donate my money at a time when it was uncertain if they would even survive -- let alone be successful).
Whenever I see Jimmy Wales' face in the current ads my gut reaction is that I'm not going to contribute to his blatant self-promotion.
I don't know Mr Wales and I have no opinion on him as a person, but I can't help but recoil every time I see his face on Wikipedia. It just doesn't bring out the philanthropist in me. Sorry. I'm probably a bad person. Or something.