Lightroom 3.4.1: On Win7 systems both the 'Edit Keyword Tag' and 'Rename' context menu items (when right-clicking on a keyword in the Keyword List) both produce the same result, specifically the Edit Keyword Tag dialog box. The 'rename in place' capability of LR2 seems to have been lost.
A minor issue, as the Edit Keyword Tag also allows renaming, but mentioned for complete accuracy.