Possible yes, but not exactly easier than using a dedicated 3D engine. The easiest and most accessible 3D for non-hardcore users would be to use David's Wolfenstein engine to recreate the look of raycasting, but even that's just a 3D projection of a 2D game.
3D effects like these are really nice looking, and technically impressive, but to implement actual gameplay with collisions and such would just be making extra work for yourself. There's no need to reinvent the 3D wheel when there are already so many rolling around out there.
The fact that you can add some cool 3D effects to spice up your game is a nice perk, though... buildings, terrain, star fields, etc. But those are all just 3D icing on a 2D cake. A perk is all it is.
Of course, there's nothing stopping some smart guy out there from making a plugin that can load model files, move them in 3D space, and detect when two models are intersecting. It's entirely possible, and that's what open source is all about. Even so, it's not like Construct could ever compete with other 3D engines that focus solely on doing 3D.
...Unless there's some magical way to merge Construct completely with an existing open source engine like Irrlicht or OGRE or something, so you can use Construct event sheets to define game logic and control specially crafted objects that plug into their engine. I have no idea if that's even possible though.