HoN is still different from DotA, with a bunch of broken heroes.
And this is only my guess, but I think you enjoy watching LoL more because you know the game more. If you've ever played or watched DotA, you'd know that it takes a lot more skill (and patience for the WC3 version due to mechanics that can't be changed). As long as you watch a high-level game of either, it'll be entertaining both ways.