Re: Do we need some kind of metadata controller in a 10 Gbit based shared storage network?

exactly. if you are using a managed volume(s) share via the server itself over say SMB then you do not need to establish a storage area network with metadata controllers.

I would guess that what you propose will work with a limited number of clients with this scenario, but if you go beyond a few clients a SAN will give you a lot better performance but will also require primary and redundant MDCs.