Personally, I think the concept behind Daikatana was cool. A magical sword that lets you time travel to different eras, with different visual styles and matching enemies. AI teammates with unique personalities that would help you. A wide variety of weapons to use, from the different eras.
The problem was in the implementation.
If done correctly, where the game play was something like that of the Jedi FPS made by Raven, with better AI companions, it could have been awesome.
Instead, it ended up as a game that looked and played like a Quake II mod gone wrong.
Now, if Romero were to do a Daikatana II and get the guys from Raven who worked on their Jedi games involved, that would definitely pique my interest.