Seems reasonable to me. YourKit generates a file in a separate location which developers go and collect manually. I don't have experience with any other profiling tools, so I don't know how many of them do/don't respect a file= parameter like hprof does.
Looking at its documentation, jprof seems to generate several files in the working directory, but specifying the filename of any one of them is a pain. (It's got a lot of file prefix/suffix arguments.) So it's unlikely that jprof would work with the downloadProfile() as-written anyway. I don't know what other profiling tools are commonly used, so I don't know what else to check.
So are we sold on "check for hprof and file=%s" arguments, and select downloadProfile() based solely on that?