We had done alot of testing using backupexec and the plain throught is that file level backups are never going to be super fast even over FC. The more smaller files you have the longer it will take to backup. The bottle neck we found is that with data drives with lots and lots of small files ie 300,000 to 500,000 files there is a lot of running around going on even with vcb. For example a system with about 500,000 files took us 3.5 hours via 1gb lan backup using BE11d, then once that same machine became a vm and then we tested 4gb fc file level backups and the fc speed was faster but the total backup time became 3hours vs 3.5hours. So we now do fullvm backups with are way way faster than filelevel. You can mount the images and do file level restores :).
You might want to consider s CDP option of b ackup exec or r1softs CDP server they do block level backups. We really like veeam backup as its cuts out having to dump the full vm to disk before backing up. and it has data deduplication built in. We are only waiting for email notifications 