2
Short answer: No, not currently
Longer answer: Since a module is detected by being located as a subfolder to modules containing a file called xoops_version.php, moving them to the root will mean that
a) Lots of code will have to be changed - both in the core and in the modules themselves
b) Whenever the module listing of all modules occur, that is not only the installed modules, XOOPS will have to go through each and every folder in the root looking for a xoops_version.php file instead of confining it to one subfolder - possibly the only problem here is in modules admin, which may take a bit longer to load