Most 2.5D games are seriously clunky and would've been better off just being in 2D (like many games of the PlayStation/Saturn era). Sure there were some good ones such as Nights and Klonoa.
Not to mention The graphics were so much better in 2d during the 3d era of gaming that it played out even more perfectly cause you got a game that fell's 2D, looks 3d, but without clunky graphics.
This doesn't make much sense to me, sure the gameplay was generally much better since they hadn't really figured out the whole movement in a 3D space thing, but the graphics were still extremely ugly 3D. You got a game that played in 2D and felt 2D, but looked ugly, although was also given the freedom to loop around itself and go "further into the screen".
I'll take 2D graphics and gameplay any day over 3D graphics with 2D gameplay.