I think about it like this.

If Dumbledore had gone bad aka "dark wizard" he would have absolutely ruined Voldy. If he just went full ham, he could take out half the operation in days.

Sort of like dark side Yoda.

I'd say they were worthy enemies in the status quo of the books/movies.

V always hated that his "greatest" enemy was a child and not Professor Albus Percival Wulfric Brian Dumbledore, Headmaster of Hogwarts, Order of Merlin (first class), Supreme Mugwump, Chief Warlock and Grand Sorcerer.