I just want to point out that Construct already has a real-time 3D view in the editor - drop in a 3D shape and scroll around, and you can see you have a 3D view there. It doesn't however have a free look camera. That's a fairly significant amount of work to implement, but it's doable.
Once you do something like a 3D view in the editor, I assume there will naturally be a lot of follow-up feature requests that will amount to implementing a significant portion of a 3D engine. That is also possible, it's just a great deal of work.
We've so far avoided going too far in to 3D features so we don't spread ourselves too thinly - making a quality 2D tool has for many years been more than enough work, and there's already years of further work submitted as feature requests. We wouldn't want to spend years working on advanced 3D features while the rest of the editor was lacking the basics, or was full of bugs and limitations that were neglected in favor of shiny 3D stuff - that would overall be to the detriment of the product. Despite that, we have still gradually done a bunch of 3D features already, including Z elevation, 3D mesh distortion, 3D camera, 3D shape, and even 3D audio playback. With those we took the time to ensure we did a good job, carefully considering the design, ensuring they integrate nicely with other features, dealing with bug reports, doing follow-up feature requests, optimizing performance, etc.
However Construct is a pretty mature product now. Perhaps risk the rest of the product suffering or getting left behind is not that significant a concern any more. So perhaps we could more seriously consider doing more work on 3D features. If that's of interest to you, then I'd suggest filing feature requests the usual way, as it helps us gauge the interest relative to other features, and especially which particular things to work on next. For example which is more important: a 3D editor view, 3D physics, 3D collisions, 3D particles, 3D models, 3D lighting, or something else? There's years of work to be done there, especially if it's to be done to the same quality as the rest of the engine, so just choosing what the next single thing should be is a significant decision too. Let us know what you think!