Basically you're right. There are still times you must manually edit the multipath configuration. Generally, you shouldn't have to do this. I depends on what type of storage you're using. Yes. The VM Manager in 3 must be used to create OCFS files system for repos and storage pools. You can not create a OCFS lun and then present it to the VM Manager. You can manually configure local file systems and then attach them to individual guests.... but they can not be used for repos or storage pools.
Actually, the 3.2.8 update has moved all the multipath.conf files to .rpmsave on all OVM servers I had updated - that was kind of a surprise, since that had never happened before.