Er... which Mediamax? The one in current release, which has not been recalled, is a very different beast from what you describe.
"MediaMax allows you to copy music, "
Per the EULA, with unwarranted restrictions.
"transfer to all portable music players"
No. As presented on the CD and under the EULA, no. Per the Sony-Apple conflict ipods are excluded by the EULA.
" and remove the software with the uninstaller."
As presented on the CD and under the EULA, no. There is no uninstaller, nor is one referred to.
" What specific road block is in the way of version 6? "
As long as the settlement provisions remedying the above are followed, none :)
SuncMax had incidentally met some of the provisions, but they were either "under the counter" (music to ipod) or after the fact (uninstall)... and nothing for the rest of the provisions. The provisions must be met in the version of Mediamax 6 distributed on CD and the EULA must match as well.