there is a lot to be done with c3 and of course the sky is the limit. I dont understand some people here with the argument that scirra is only a couple of guys. Telling this whats your point?That they are incapable to do next level things? when i say next level things i mean the possibility of 3d objects (for anyone who wants it) better mobile exports, better image editor, better lighting system, mac linux versions, or whatever anyone wants..
Construct 2 has a very reasonable price. It's the most affordable paid 2D engine if you consider it's features. Being affordable means more limited resources for the developers. And hiring more developers is expensive. Just to put it simply.
last day i saw spark engine site they had release an alpha i think and they promise tons of features and the programmer is one guy aris kostakos..So what is really the difference? its only in time i think yes a team can achieve better results in less time but 3 years now we are saying again and again the same things about mobile exportes and nwjs and when c2 will run on mac.
Spark Engine has a lot of potential and the big difference between it and Construct 2 is that Aris built up Spark from the beginning to support 3D (and it's also based on Haxe, not HTML5). And now he builds the editor to make people able to use the engine. It's a long-term project and rewriting a whole engine just to support 3D is not an easy task. However we saw that 3D can be done with plugins like Q3D, so I'd suggest if you want this kind of feature you either go with a plugin or learn UE4, Unity at the moment. C3 and Spark are a long way off.