I've done some very very very preliminary investigations, and I don't think it will be possible to mod it back in. At least not easily. Haven't looked elsewhere yet, but the main difference looks to be the file GovernPlanetWnd.xml in the Screens directory.
I tried a blind copy-n-paste from 1.3.2 into a newly created Screens directory in a mod folder and that didn't work. Tried to put GovernPlanetWnd.xml in a couple of other places in the mod directory structure and that still didn't work.
Even tried to modify GovernPlanetWnd in the base game directly and that still didn't work (though I might try that again in OFFLINE mode to see if the file isn't reacquired).
Long story short, I suspect I know what SD changed (though there might be other places where it got changed as well - haven't looked that deeply yet). I don't know how to change what they changed, however.
Not that I personally care too much about this as it is mostly an academic curiosity for me (I won't really miss the wheel except in the very very early game). But for those who are really, ahem, steamed about this, there's the place to start looking.