The problem with simply removing the "or later" clause is that each version of the GPL is pretty-much inherently incompatible with other versions. The GPL basically allows no exceptions to any of its terms (ignoring some of the explicitly-allowed-variations in the GPLv3), so GPLv4 will be incompatible with GPLv3 and GPLv2. If you use the "or later" clause, this doesn't matter, because GPLv2-or-later code can be used in a GPLv4 (with or without "or later") project, so all the "or later" versions are compatible. But without the "or later", you get a combinatorial explosion of license incompatibilities as the number of versions of the GPL increases. Which I think is probably a very bad thing.
That's why I suggested above: if you don't trust the FSF to do the right thing, then, instead of simply removing the "or later" clause, replace it with something that says "or any later version that meets [list of criteria I consider indispensable]". For example, if you're a big fan of Tivoization, you could say, "GPLv2 or any later version that allows [tivoization]". Then, if the FSF had a change of heart and decided to allow tivozation (perhaps as an option) in the GPLv4, your code would automatically be compatible with v4 (or at least with v4 projects that exercised the tivoization option).
Bottom line: "the FSF might do things I don't like in the future" is a mostly-hypothetical bad thing, while removing the "or later" clause is license proliferation, which is a right-now bad thing.