I've never used a Mac but on both Windows and Linux all graphical file explorers I've used have used F2 for rename (I think it even means rename in some other programs that don't deal with files) and especially with the visual feedback there's never any confusion about whether you've started the rename operation. I also don't think I ever have a problem with accidentally starting a drag - again, perhaps a Mac problem, maybe with too small of a pixel count before starting a drag?
Realistically, some things are better done on the command line and some are better done in GUIs and this is just something much better done in a GUI. Of course if you are already in the command line then the overhead of switching to a totally different program is huge compared to the saving once you get there. But I find many sequences of simple file operations are easier in a GUI than the command line, and it's just as silly to religiously rule out GUIs as it is to never use the command line.
Realistically, some things are better done on the command line and some are better done in GUIs and this is just something much better done in a GUI. Of course if you are already in the command line then the overhead of switching to a totally different program is huge compared to the saving once you get there. But I find many sequences of simple file operations are easier in a GUI than the command line, and it's just as silly to religiously rule out GUIs as it is to never use the command line.