Let's see this from a different side:
When you're developing a mobile game and it runs smoothly on the android device (in the browser or direct apk build) - you know exactly where you will end up with performance. With C2 this is not so easy - you are forced to export regularly apks and check for perfomance issues. What runs fine on your x86 development pc rig / surface tablet could run with poor performance on a android/iphone or whatever mobile device - so for me this is a huge improvement on mobile game developement we will get with C3...
For sure there are still so many things we DONT know about C3 - so it's difficult to imagine what the cloud / browser based design really can improve for mobile game developement.
Personally I don't want to develope on a mobile device (even if it is a surface). Here in my institute there are some people using surface tablet pcs... And yeah they suck . Shitty keyboard, small screen - meh...