I always thought about that, and I do believe that sometime in the future coding might move onto tablets/phones. Just not yet, because we require a lot of power and space in order to code and the tablets just don't offer us all we need yet. Besides that, there are a few hurdles that we would need to get over in order to make coding on the tablet/phone more viable.1) That keyboard
I dunno, but the touch pad keyboard just doesn't match up to the real thing. The technology for the keyboard is great for short messages (barely), but when you are talking about trying to type out an essay, coding, or gaming.... It becomes cumbersome quickly. This is one of the major hurdles that needs to be overcome. For those who think bringing an outside keyboard is an option, I say it defeats the purpose as we already have laptops that perform the same function. Also the keyboard on the tablet takes up screen real-estate which brings me to...2) Screen Size
The other hurdle is more to do with aesthetics since, as a programmer, I like my screen to be as big as possible. They weren't joking in the movies when most people who can afford a computer set has a movie sized screen to code with. For me, the bigger the screen, the less I have to scroll. Coding and scrolling just don't mix with me... and if I have to make the text small my eyes'll bleed. This goes directly against the whole tablet philosophy of getting smaller and smaller. 3) Comfort
The last hurdle has to be how comfortable it is to work with a tablet as a keyboard. In reality, if you are holding it, you have one less hand to type with, forcing you to put it down. So, in most cases, the tablet will have to be on an sloped surface and/or supported for it to have any sort of viable use. Secondly, a programming session usually lasts hours, which means a good power supply would probably need to be nearby. Finally, we need to make sure that it is angled in a way that our eyes and necks don't get tired looking down at the screen. To be honest, though... getting all these conditions right is a challenge in itself just for one session.I guess what I'm trying to say is...
The tablet technology is great, but it is just not for programmers. Everything that the tablet promotes (small, portable, and quick) goes against what we need as programmers. Not that I wouldn't want a portable tablet to code with, it is just that if we try to make the tablet into the next laptop the flat surface really makes it difficult.
The tablets strengths come in quick-session gaming, drawing art, and exploring the web. I realize that the tablet is really really good for doing those tasks that you can take breaks. Any task where you can rest the tablet down or holding it at different position when you are tired works great. Furthermore, any game or application that allows you to do quick sessions with your hands also excel on these devices. Everything else ends up tiring your eyes and/or limbs out too much.
Anyway, if we can look past those issues, I think the tablet would be great. Maybe I just have to wait for holographic technology so we can beam the screen to a wall or something