Well keep in mind, that of all the types, the ENTP's are also the ones most likely to fanatically desire to improve themselves. If the little do-gooders want to impress their desire to help upon anyone, it'd be the ones who both look the most broken, and are most interested in accepting being 'fixed'.
Of course, it doesn't help to pick the ones most likely to argue the point to ensure they're not changing simply for the sake of change either... change is great, and tradition can be silly, but there should really be some kind of purpose behind WHY people change...I'm not going to just drop all my values and beliefs and adopt yeurs just because yeu tell me to... yeu'd better have a very good reason for thinking I should. If yeu can give a strong enough argument that I can't refute, I'll look into the idea further, and do some research on it. If not, I'm not going to waste my time. Just saying "I think yeu should be more like me, because I think I'm awesome" is just ridiculous. Drop the god complex, seriously. The saviour one, with needing to rescue me from myself, doesn't help either >.>
If the first thing yeu say is "I don't agree with yeu, yeur mind, yeur beliefs, or anything yeu care for, and think it should all be burnt in a fire..." yeu don't immediately then go "incidentally, how about yeu convert to be a me-clone? Yeah that'd be swell".