Despite all the ranting and raving I might be (or am?) known for about the performance and export options of Construct post-Classic, I actually agree with this thread.
The cloud services, and potential for a Google Docs-like real-time collaboration system, is what could be really powerful, in addition to the added control over the interface that plugins have (because it's in a canvas already).
Selling those services as a subscription "Construct Cloud Services", and maybe even giving priority/premium support to users of that (since Scirra can literally download and run/check out the projects stored on those cloud servers, assuming the client allows it) would be a professional service sold at a professional price.
Otherwise, I don't see it being a long time before other engines do "what C2 does" and have the added benefit of native export to:
Consoles (Xbox One, PS4, Switch, WiiU, New Nintendo 3DS, PS Vita)
On top of WebGL export, which is the only one Construct actually "has" (without wrappers)