I for one is very interested in development on a mobile device.
You say how can construct 3 run on mobile and not implode on itself after 20 events. You should probably give mobile devices more credit then this.
Just remember the games you are designing can be exported to mobile. That statement is almost like saying, don't bother designing a mobile game if you are using a PC to designing a 20+ event game.
I'd also like to point out that you can definitely connect a mouse and keyboard to a tablet as well a phone simply by using a OTG cable or Bluetooth! There are also devices like the "Superbook" which will make you mobile device run much like a chrome book or laptop using just your phone/tablet.
Also note that while a device maybe 6", a lot of these devices also run at 1080p resolution or even 2k res.
Plus the layout for mobile seems very sleek and by no means is anything hard to read. Add your mouse and keyboard and you got a nice setup to develop on the go.
If I have to make a game for mobile I will use a pc or a laptop as the 90% of the users here... are you serius? take the phone 6" with the mouse or the keyboard? and maybe why not... take an extra screen to use it? is not easier to use a laptop?!? this is not a special feature, is normal, construct3 run on a browser, what is new? nothing....
I want to see the difference between construct2 and construct3, I don't care if now construct3 can run in all of the device in this world... all of the people here who use construct2 use a pc to make app...so? I can understand to make the software compatible with mac... but for the mobile support, please, don't... ask a graphic designer to make some work in a 6" device...
I think 
Ribis what is trying to say, is why scirra gave more priority to features that not everyone will use at list very often, because the heavy job for development of your projects will most of the time done on PC, laptops.
so why not give priority to the most crucial futures that every single one needs like Easy exporters to mobile and more stability in mobiles.
This is the frustration that most of the C2 users are facing right now, that's why you see everyone is going nuts on the forum.
Most of the developers were waiting for C3 for a long time, to see if they will address this problem first. that's why you see the opposite reaction from C2 users, instead to been celebrating the C3 news they are disappointing and I agree.
The development on phone, tablets is really cool feature to have and will be handy some times, but what's the point if you can't start to develop a game for mobile because of the trouble you go thru to release it on mobiles. why not spend that time concentrating on the most important mobile export and stability.
The way I see it is like this:
-should a start a game for mobile? not is to much trouble yet, especially for none experienced programers.
-Then now comes the question, is it worth the feature to develop on tablets, phones, etc. for me...?
no yet because I didn't and I can't start any project for mobiles because is so much trouble still to release them on mobiles platforms. do you see were I'm going? so if there is no game to work in, doesn't matter how many cool features the software will have, will be not benefiting in any way until the bigger problem is address it.
Finally, thank you....
I think, if scirra change just the layout design of contruct2 and put the exporter works, everybody will be happy to buy it...let's see if the export option will be the same as construct2, because if this, trust me, nobody will pay the second time for using it.