Yeah, I agree with what's been said thus far. In my opinion, full 3D in Construct is not a very realistic goal.
However, being able to make "2.5D" games in Construct (or just 2D games with 3D models) would be good enough for me.
At the very least, I'd like to be able to use character models in my games instead of sprites. Especially for RTS games or games with a top down view, or maybe even for huge bosses (like a giant enemy airship that can rotate around and fill the screen with bullets) in 2D side scrolling games.