I think you are right. I remember Duke as technically more advance than Doom 2

I found something here: http://doom.wikia.com/wiki/Duke_Nukem_3D

"While Doom and Duke Nukem 3D feature similar technology, Duke Nukem 3D could in most respects be considered technically superior. The player can jump, crouch, and aim up or down. The rendering engine features slopes, overlapping and moving sectors, arbitrary scaling of textures and strong scripting capabilities"