NiceOne (and others): If you don't like leaving the bug in, what about my suggestion of making it an option, like they did with culture flipping? Obviously, there are strong opinions on both sides, so why not leave it up to the player which he prefers?
If Firaxis 'fixes' this, those of us (a clear majority, it seems to me) who would like upgradeable armies are f***ed. Whereas, if they leave it in (or better yet, make it optional), opponents of upgrading can always decide not to use it.
Personally, I'm always pro-choice... as opposed to "we know better than you how the game should be played"!
And if the AI doesn't know how to upgrade their armies (BTW, who says that can't be programmed if you make it a regular option?) - so what? It doesn't know how to use arty, either, and I don't see anyone proposing arty should be banned..
Personally, I'll take any legitimate advantage I can get playing on Deity level..