I'd buy an iPad Pro tomorrow...if only it ran Xcode. But I can't justify $1200 or more if I doesn't help me to get my work done. At that price, and admittedly for my purposes, the iPad Pro is just a very large and very expensive gadget.
The really annoying thing is that these days a late-model iPad probably has most of the horsepower needed to pull it off.
For me it's "I'd buy an iPad Pro tomorrow...if only it ran Xcode [and had a terminal]." It can be heavily sandboxed as far as I care, I just need a proper Unix terminal. The trouble with Xcode is that it just needs so much screen real estate, I just can't see it working very well on iOS.
I assume you mean a terminal for the local machine, not an SSH session to another machine, in which case Panic's Prompt is what you want for SSH.
I'm with you in that I'd like a local terminal, but I could live without if I had Xcode on the box and some sort of full-screen editing mode. Working with storyboards would indeed suck, though.
There are terminal emulators on iOS already, that's not the issue, but not having a local filesystem means it's only useful for remoting, there's nothing a terminal will let you do on the device (unless it's jailbroken)
The really annoying thing is that these days a late-model iPad probably has most of the horsepower needed to pull it off.