I've never modelled so much as a polygon, so I don't think Construct's going in a Blender type direction. If you want a full on 3D first person shooter with world editors and 3D collisions and the works, Construct isn't going to be a good choice for some years to come, I guess. Part of the problem is you won't get very far - in fact I don't think you can get anything drawn at all - without some pretty heavy math involving matrices, vectors, euclidean angles, vertices, and possibly quaternions (I say possibly, because I'm not sure what they're for or how much they're used in 3D gaming). I'm of the opinion that a completely flexible 3D game maker that is easy for a beginner to use is not possible like it is in 2D, except with limitation. As far as I know, programs like FPS maker work by hiding this work from the user, which makes it less flexible. I don't think you could go and make Crysis in any of those programs without dealing with the nuts and bolts yourself.
Oh, I wasn't suggesting that Construct do like Blender does. I was just making conversation. If you want to do what Blender does, use Blender. In general though, I think you're right... the more work you take away from the user, the more limitations you create.
As a hypothetical though... Could a 3D game maker be made with the same sorts of features as Construct, using the same sort of event structure? I think it's not only possible, but likely to happen eventually. (There's already a very simple 3D program called Alice that uses event-type coding, and while it is possible to make games with it, it's so limited in scope that you probably shouldn't even bother.)
The biggest drawback for noobs would be creating the actual content. Creating content for 2D is already the major drawback of any game maker. By comparison though, making sprites is easy... making textured, rigged, and animated models, and 3D maps and such is not so easy. For beginners, anyway.
Procedural modeling and animation could take some of the pain out of creating content (think building your creatures in Spore) but that's something for the not-so-near future. I think it'll come around eventually though. Just like game makers took the tech out of coding games, in effect making game creation more accessible to people, procedural modelers will take the tech out of modeling, making 3D more accessible to people.