In retrospect, I have to say that Curse of Darkness is probably the Castlevania game in recent history that had the most promise. It could really have been the first successful "SotN in 3D". They brought back the level system, the interconnected gameworld, the "anti-hero" main character, the fantastic soundtrack (yes, I was not a big fan of LoI in the music department, sadly). And they got rid of the fixed camera.
With a foundation like that, together with the lessons learnt from Lament (and Nanobreaker), CoD had everything going for it and should have resulted in a lot of great things. But the finished product absolutely baffles me. Most of all the friggin LEVEL DESIGN. IGA already produced a flat, empty 3D Castlevania and should've stepped up his game by this point. I somehow feel that Curse turned out EVEN flatter, which is unheard of. The game is also arguably uglier than Lament.
I don't hate CoD (I adore the soundtrack from start to finish!), but thinking about what could've been definitely puts it at the very top of my personal "Most Disappointing Castlevania games ever" list.