hedwards: I was a bit shocked that anybody on this forum would be suggesting that a game could be something other than top down and tile based and still be a roguelike. By the OP's standards, Diablo would probably be considered Roguelike even though it's a different genre entirely.
Fenixp: Well yes, shockingly enough I care about gameplay (turn-based combat, tile-based, permadeath, random generation) to classify a game as a roguelike, not perspective. Yes, Dungeon Hack was all of those things. Yes, it's actually not particularily difficult to change perspective in a roguelike without touching any of its base qualities - well unless you want to suggest that tower defense games are 25% roguelikes because of the way camera is positioned :-P
I know, shocking! I do wonder what your reaction to actual problems would be like if all it takes to shock you are people with different opinion :-P
The perspective was an integral part of the genre.
Bending the definition to that extent leads to a muddying of the waters. When somebody tells me that there's a roguelike, then I expect it to have something in common with Rogue.
And yes, it is difficult to change the perspective, a large part of that game was seeing all around you knowing that those tempting items could seal your fate. Being locked in to being able to only see what's directly in front of you greatly diminishes that aspect of the game.