> [...] We had to either go GPL v2+, which assumes the FSF will never go crazy, [...]
This is a rather common common misconception. If you use the "Version 2 of the GPL or any later version"-clause in your specific GPL licensing lingo, then any re-distributor may CHOOSE to distribute under GPLv3, or GPLv4 (if it ever exists), or, for that matter, also GPLv2. You're not bound to re-distribute under GPLv${latest} because of that phrase - so it is, in my pov, completely safe to go with the "or later"-clause. (But that also may be because I do trust the FSF to not "go crazy" in the forseeable future :))
A future GPL v4 could say "Your code can be converted to the MIT license", or even "your code can be used by company X" in the event of a takeover (which I don't consider an impossible option).
> "your code can be used by company X" in the event of a takeover
The FSF is a tax-exempt 501(c)(3) charity; if it would institute policies to benefit a single for-profit entity, the inevitable IRS audit would be excruciatingly painful and likely result in jail time for directors.
This is a rather common common misconception. If you use the "Version 2 of the GPL or any later version"-clause in your specific GPL licensing lingo, then any re-distributor may CHOOSE to distribute under GPLv3, or GPLv4 (if it ever exists), or, for that matter, also GPLv2. You're not bound to re-distribute under GPLv${latest} because of that phrase - so it is, in my pov, completely safe to go with the "or later"-clause. (But that also may be because I do trust the FSF to not "go crazy" in the forseeable future :))