WoW 8.2.5 is coming on 24 Sep 2019. On the PTR it currently has TOC 80205, vice 80200 for the live 8.2.0.
Would it be possible to add 8.2.5 to the version dropdown when uploading files?
I hope your idea gets traction because I do the same thing as you (conditionals to check game version) and would love to automate the game version in a TOC file.
I think an even better solution would be if Blizzard modified the TOC file so you could explicitly state compatibility with multiple game editions.
There is now an option to set compatibility for both Classic and Retail in the file upload.
However, its currently broken. It generates an internal server error if you don't choose that it is compatible with BOTH. (ie, you must pick a version in each, and not just one or the other)
I am currently disabling this addon pending the rewrite, but I am happy to help with alpha testing any early partial versions to help you identify problems early on.
I just started following the project page (specifically file uploads) on WoW Ace, so I'll know if you are pushing something for people to toy around with.