After you go through the process for the first time, you realize that it's a pretty easy thing to do which means it wouldn't be that much more work to go back to an earlier version or to find another rom that other users are recommending.
I haven't really explored that on the Moto E though. My aim is to improve a more recent device that other users report substantial improvements to with unofficial upgrades.
I have 2 of these-- a Boost Moto E2, and a Verizon Prepaid. I remember that the Verizon one has GSM radios-- but it appears that some folks in the linked thread have problems getting through the process on the Verizon version. I don't remember whether the Boost version has radio hardware (with a firmware block), and whether the bootloader can be unlocked. I also don't know if flashing bypasses the SIM lock on either/both. I'll have to do some more reading on the long thread.
Unlocking the bootloader is the first step, and if you can't do it, then you won't harm your device trying.
I did this on a Sprint Moto E. It still worked on Sprint afterwards but did not work with a GSM sim. I didn't look into it too much as it was the device I chose to learn on before doing this on a device I wanted to use. I do remember reading on xda developers of people who figured out which models of the Moto E might work on other networks if flashed with the appropriate rom.
Although I didn't try it, I'm quite certain that if you got hold of a rom meant for another Moto E variant and installed it and it didn't work, it would be easy to wipe it and install another. That's part of the functionality that unlocking the bootloader and installing a custom recovery gives you.
Interesting indeed - thanks for that bit of news Isamorph !!
There's an old 14" NB hanging around here that would be perfect for that re-use.
Aside of that & as silly as it may sound, the newer Chromebook that it sitting around here would be more pleasant for my uses if it could somehow be changed to running straight Android - which I have not looked into at all, but failing that possibility it will just get re-done with Linux as the browser OS doesn't suit my needs on that device.