I don't know how you feel about Diablo, but Diablo came about because someone took the formula (Roguelike) - (Turn Based) - (Permadeath) + (Graphics) you know?
Personally I like Diablo and Diablo II. Also I see roguelike features in it. But a roguelike they are not - somone even coined the name "diablolikes" for later projects that used the Diablo specific features of being realtime fast paced action games.
I don't say things that are not roguelike are bad. But I don't think every good game must be called roguelike just because it has a few roguelike features.
Diablo developers in an interview said they were inspired by earlier games, including NetHack. So that's where some of the ideas come from. But they didn't claim to make a roguelike game, but something new.
To be fair one must admit that Diablo II has a permadeath mode, and there is a group of players playing this style. So one cannot just say the permadeath feature would be missing. It became optional, though.
Having said that, I want to say also that evolution is good. Just once something evolves sufficiently far, it needs a new name - it will not be a roguelike anymore, since the comparison is fairly fixed, and if there are too many difference it's just not enough "like rogue" anymore to get that name.
But yes, go an build on the old ideas, stepping forward and creating something new. Make good games, and it will be fine