I don't want to force the mission to be balanced. That's up to the FREDder. The problem is that at the moment what the FREDder selects in the team loadout and weapon selection options and what actually happens in the mission are two completely different things.
Make a mission where Alpha has Ulysses with default weapons and Zeta has Ares with Maxims and Kaysers. Make sure neither side has any weapons selected in the loadout editor. When you play the mission you'll find that the Maxims and Kaysers are gone and replaced with whatever you gave Alpha wing.
My mistake at the start of the thread was assuming that this actually worked in retail since I don't recall ever hearing any complaints. It never did. It has always been broken. That actually makes my life easier as I don't have to worry about breaking unbalanced missions with my changes, they're already broken. The second the
FREDder saved them this bug would have corrupted them. The fix I have in mind won't break them any more and might even fix a few of the broken ones.
The limit for TvT is two teams. In fact
have made a bunch of assumptions throughout the code that there are only two teams, each with only one wing throughout the code. Goober's been removing them for a while and I'm now doing pretty much the same thing whenever I find any code that assumes it. It doesn't mean that we'll get more than two teams any time soon but it does mean that if someone ever does try to implement it they'll spend less time dealing with new bugs in Mantis.