The most disappointing aspect of Draconus has to be the choppy framerate. With a next generation system like the Dreamcast one would expect more. At first sitting it's going to be irritating, but after subsequent playtime you get used to it. It just doesn't seem realistic. Sure, textures are extremely detailed, but I could've gone with fewer leaves in the trees if it meant a faster framerate.
Clipping is also a problem.
I actually managed to get Cynric in a tree. Getting him out was a challenge in itself. Control is an uncomfortable, daunting task. Circle strafing becomes an exercise with the shoulder buttons and pulling of combos results in sore knuckles. Granted, this is probably Sega's fault due to the DC controller design, not Treyarch's implementation of control.