Wow... that makes IE10 sound really good... but I guess that is the point.
I have to say that I am quite disappointed in Firefox when I installed it on a Dell XPS 12 Windows 8 machine with touch screen. For some reason, the browser tabs are like double the height they should be. I have no idea why, so I will be using Firefox less on it and IE10 and Chrome more, at least on the Dell machine. I did try to figure it out but couldn't find a quick & easy answer.
By developing for IE10, do you mean developing more HTML5 applications that, in theory, are suppose to work in other HTML5 browsers as well? I think that might become more common, but I think there's still also a significant problem with various browser bugs and varying levels of standards support, but I suppose that's improving.
I can't see someone developing only for IE10, at least for the general web audience.