I work on two 30"+ monitors; 11-13" for a secondary machine is fine, but if it's my main I want bigger, and if I'm hooking all that up I might as well work on a desktop system that has a much higher TDP limit; power and flexibility-wise I don't think a tablet is something I'd be happy to settle with. This is before I get to the OS even, where I don't like not working with a full-fledge file system and a command line. And proper multitasking too.