Very interesting thread.

A couple (hopefully new) comments:

1) if perforce had an ability to determine and use the closest common ancestor
(base version) when doing baseless intergrations, then the integ-and-delete solution would work
much better for renaming. It would not completely solve it, but it would become more user friendly and adequately address more situations. I might even say
that it may be acceptable :-)

2) if one _needs_ versioned directories and changesets out of the box, then one may want to look at accurev. accurev and perforce are very similar, but accurev has an implementation that considers a change in the filename to be somewhat the same as a change in the file content.

In clearcase, to change a file name one has to do something different then
change the file, namely change (version) the directory. Which as noted, causes issues when merging.

-sandy