Sirsquier
Warlord
He espoused expanding the Empire a couple decades after everyone else realized the Empire was a bad idea (though given his opponents' reasons were as much financial and pragmatic as moral, they only get half credit...), and he opposed the formation of the Commonwealth. He also held racial views that were sketchy even by 1940s standards. Also, while I personally don't think it's terribly relevant, he wasn't the nicest person and had a drinking problem. I see him as a great deal like Lincoln: he provided strong leadership when his country needed it, but he was personally ambitious, ruthless, and unprincipled. At any rate, virtually anyone I've known from Great Britain loathes Churchill, and a lot of Britons would be very upset if he were chosen. (While I have no interest in seeing Churchill chosen given my dislike of modern rulers and civs, I personally don't think that a leader's popularity in their home country should be a factor in selecting the leader...but I don't work for marketing.)
I agree with you on the point of selecting leaders based off popularity. It's not exactly the best way to do it. I also prefer most of the older civs/leaders. With exceptions for the U.S., Gran Columbia, and Churchill (if he were to be in a game). Personally, I just feel most of the modern civs/leaders don't live up to the older counterparts.