Well, not really. Now when strings are correctly branched, Moodle developers can modify the string for a given branch only. For example strings can be reworded for 2.1 without affecting 2.0. This was not possible in Moodle 1.x because we used a single branch for translations of all Moodle versions. So we had to introduce new strings instead of altering the current ones.
Hmm, although... The merge tool could check the original English text. If it is identical at several consequent branches and there is a modification in a translation of one of them, it is reasonable to assume that the maintainer wants to accept the change for all branches.
Example: let us have a string [foo,mod_bar] that has the English text "Foo" at 2.0 and 2.1 branches but "Frog" at 2.2 branch. It is translated as "Bar" at all three branches. A contributor submits a translation that changes the translation at the branch 2.0 from "Bar" to "Beer". There should be a way (probably at the stage page) to propagate such change to 2.1, too. But the propagation must not affect the 2.2 branch.
So I can see it as a button "Clone translations" at the stage page that would do this job for all staged strings. Ideas? Contra-proposals?