I have to disagree. I think simple 3d games can be made in construct and quite well with only minimal new features. Try this demo I whipped up:
Wasd to move, space to shoot. Apologies for the low res earth - had to keep the file size down to upload it to the board.
All that's needed to make an actual starfox game is the ability to display 3d models, move them more acurately through 3d space (like a 3d bullet movement for the lasers and to steer ships), 3D collision detection, and a real 3D camera (everything is faked in that example). I could have even done without the 3d collision detection and used detector boxes and checked the Z position to check if the lasers hit the cubes, but didn't bother, because it's mainly to show what could be done.
And I made that in about a half hour, and could have done it quicker. True, it's no crysis - but it looks cool and could be fun, and construct can already almost do everything needed for a complete version. I honestly believe if I spent some time on that, I could get a 3D starfox clone going that would be entirely playable with construct as it is right now. It wouldn't LOOK like starfox - but it would play like it.
(Captainoblivious, this was inspired by your efforts.)