Call me a cynic but why would I need this ? A linode/ec2/azure linux vm and a Terminal is all that I need to do web development these days. Setting up a web server is such a breeze already. Is there a need to simplify it further ? just asking.
Yes. For mobile devices or netbooks (chromebooks), cloud IDEs are pretty ideal.
on chromebook - crosh is sufficient.
on mobile devices (I hope you mean tablets) iSSh and other terminal clients should suffice.
I'm not downplaying this requirement but just wondering to what level will this get simplified :).