I sympathize about not running local dev environments, but for the actual work I do the apps won't run on a laptop or local PC anyway without a lot of trouble, so I'm used to working over ssh to a dev server. That works very well on an iPad, even better with a decent keyboard with an escape key.

As someone else mentioned Pythonista gives you local Python.

I work on multiple large web applications for a few clients and I've tried using my iPad Pro exclusively. I've only run into two issues that make it less than ideal: No web inspector/JS debugged in Safari (though workarounds exist they're clunky), and difficult text selection (not an issue in a terminal window with vim but imprecise and fussy in iOS apps). Otherwise it's great and I do use my iPad a lot. My main work setup is a Chromebook (Pixel Slate), which I only prefer over the iPad Pro because of the trackpad/mouse text selection and Chrome web developer tools.