I have no opinion on what religion Tiger Woods should follow. It's not my business.
All religions have essentially the same moral codes. They have different reasons for promoting them, but at a practical level, there is not a lot of difference: don't kill, don't steal, don't commit adultery, etc. They are common because, socially, they are what works.
So changing religions is not going to make a difference to the moral code that the person aspires to. Of course, this point is precisely what right wingers like to lie about: they would have you believe that their brand of religion is the only one with this moral code.
So Tiger Woods was not a perfect Buddhist. This is news??
(It was news to me that he was Buddhist, but I'll take your word for it.) None of us are perfect. Any more than any particular Christian you care to name is a perfect Christian. So, if an imperfect Buddhist becomes an imperfect Christian, that of itself is not going to change his (or anyone else's) ways.
People change when they find a motivation to change. If converting to another religion were to provide someone with a better motivation for good conduct, then I would say, "Go for it." If they find that their present religion provides them with a good enough motivation (recognizing their imperfection in applying that motivation), then they should stay where they are.
Om mani padme hum