He was getting 5.5:1 odds to call your preflop raise, so putting him on a small PP was reasonable, especially with the chip lead.

I think a decent raise on the flop would have been good simply because the only way he calls is if he thinks he's got you beat, in which case you might put him on a big PP, Ax, or a set. If he folds, then you weren't gonna get many more bets out of him unless he had you beat anyway.

Course, I probably would have played it the same way.