What about C2/C3 own exporters?
This has been done to death already. But in terms of reliability, look at the situation I described in the blog post: our own exporters could actually prove to have *worse* bugs. Currently, the major browser vendors have already implemented workarounds for a wide range of such issues like graphics driver bugs.
I don't care if it's Node-Webkit that is broken, I paid Scirra for a tool that they say will work...
Consider the exact equivalent in native: graphics driver bugs cause your game to crash on startup on *all* Intel HD 4000 series cards. (All graphics vendors have issues, don't think just AMD or Intel are affected.) After having to buy a new PC and build it with the given graphics card so we can test it, we waste days guessing what the problem might be and come up with nothing. Somebody says "I don't care if it's the graphics driver that is broken, I paid Scirra for a tool they say will work". Despite the frustration being understandable, it is a completely hopeless situation and there is nothing we can do, and it's still not our fault. As I described this is by no means theoretical, and already happened with the Construct 2 editor.
So this happens regardless of the technology choices we make, and switching to other technologies doesn't necessarily improve anything. It's easy to imagine us making some change and everything being perfect, but it could actually be worse!
In the end, even if you build a flawlessly working bike, a pothole can wreck you.
I think this is the best analogy. A bike is not useful without a surface to ride it on. But not all road surfaces are perfect, and some can damage the bike. This does not mean the bike is flawed, but you still might be understandably upset.
Why not look into Vulkan for C3?
Vulkan is only supported with certain drivers on certain systems with the latest hardware. It's promising, but I doubt it will be on a majority of systems like OpenGL is for a long time to come. If waiting for technical improvements is unacceptable, then Vulkan doesn't fix that. There's also a huge pile of other issues, graphics certainly isn't the only significant component involved. As I say this has been done to death.
I must add people here are raising issues I am not aware of there being open bug reports for. Current browsers can all hit within 0.1ms of v-sync according to my measurements. I haven't seen any recent activity in the Bugs forum regarding NW.js issues on Mac/Linux. If you have trouble please file reports following all the guidelines - sometimes we can work around them or forward on a technical report to a third party, like we just did with the iOS bug.