Touch screens can be simple enough if you get used to them, they save a lot of space on the device and I think they are cheaper than a keyboard.
Touch-swipe features will also make things much, much easier on a touch keyboard, and I'm sure it's totally possible to add linux commands or programming keywords to a swipe dictionary.
Touch keyboards can also have their layouts changed.
Other thing to consider if you're typing code, it would be nice to introduce more autocomplete to make things easier.
In the end if you really want to type, just get a real keyboard and sit down at a table. I'd also rather buy a well-made handheld keyboard that you attach to a device, but sadly I can't find one that is worth it.