Apparently, the application Terminator moves to beta:
Terminator, in case you don't know, let's you put many terminals in one window. It's full of sysadminy goodness.
From the description at Launchpad:
We are hopelessly dependent on terminals and we like to have a lot of them. Terminator is our robotic gift to an unprepared world.
$ man terminator:
Terminator allows you to manage windows using the keybindings described here: Ctrl+Shift+O Split terminals Horizontally. Ctrl+Shift+E Split terminals Vertically. Ctrl+Shift+N Move to next terminal. Ctrl+Shift+P Move to previous terminal. Ctrl+Shift+W Close the current terminal. Ctrl+Shift+Q Close the current window. F11 Toggle fullscreen
...I can't decide if this is a bad case of NIH or pure neglect...

This isn’t NIH or neglect.
This is no different to GNOME Terminal supporting tabs, which Screen can do just fine.
Some purists argue that Terminator/Screen shouldn’t be doing splitting at all because that’s what tiling window managers are for and we should all run Ion or similar.
Frankly, all of these arguments are ridiculous. Screen is not yet feature complete for splitting, it’s also a shady hack to split one pty into multiple ptys.
Tiling window managers might be fine for a workspace full of terminals, but for many modern desktop paradigms they quickly break down. I might be a sysadmin, but i still use normal programs as well and appreciate being able to use a normal window manager.
Basically, if you don’t want these features in one place, you can use them in another. I happen to run screen inside my terminator windows because I prefer to do the UI management graphically, but I don’t like tabs. I don’t care at all if some people want to use Screen instead, or Ion. Why is it bad to be able to solve these problems in a way you are comfortable with, instead of mandating that everyone use the same method?