I don't get the problem here Wandamey (or at least I don't share all your concerns about double uploads e.g.).
Please, don't take this "game" and surrounding too serious. Dopiate just developed a helping tool for authors (and some users).
Though: As Dopiate has blacklisted your addons it should be ok now. Too bad, will have to update the PTS API for your addons manually again.
Just my brainstorming
If any user updates all his/her addons to the new API (manually or by help of FastAPI, or other tools), and the addon won't work, they don't need to download anything so far.
They will just cry, blame the authors, blame ZOs, blame their wife/husband, write a bug report or spam the addon comments like before
I don't think their behaviour will change recently just because they tried another tool which changes something about addons (what they might not undesrtand as you described above).
If something doesn't work, they drop it, ask a friend, redownload it or, if they want to invest at least a bit of time, copy the error mesasge and post a comment here for the author(s).
After your update to the addon you change the version number (assuming you have and change the version number in the manifest file, so Minion can use it properly) and the user downloads the new file, which works again. So it'll be only 1 upload and download.
The users are even able to change the API of your addons manually, change the version in the manifest file or change the addon's files to their needs.
You won't be secure against manually changed manifest or lua files, no matter how it was done (by a tool like FastAPI or by the help of Notpad++ regex search and replace, or manually...).
So imo FastAPI is a helping hand for addon authors during e.g. the PTS<->live switches and the ones who use it are resopnisbile for what they do (user or author).
I wouldn't update all my addons locally to the newest API, because I don't have to if I enable "Use out of date addons" in the game (only if I need to test something).
I don't get it where this will be more work for the devs?
And if the user is willing to learn he/she will only use FastAPI once and afterwards just start to blame the authors, cry and write angry messages in the forums again
@Dopiate
The easiest thing FastAPI could do is just enable the "UseOutOfDateAddons" line in that "UsedAddons.txt" (I forgot the correct name, sorry) file
