Hi Simon,
Your spec generally looks good. The only thing to be aware of is that NFS can have file locking problems. If you're running your existing OMERO server with NFS and have enough experience to work through any future problems you should be OK, otherwise it'd be worth considering a SAN or some other local storage.
Should be fine, so far we had no problems. If we will later upgrade towards Infiniband, we might also consider to provide the OMERO data storage natively from a central GPFS file system (the IBM high-performance parallel FS). But let's see how things evolve ...
Edit: One more thing: to future proof the server you'll also want a recent OS, e.g. Centos 7.
Totally agreed, HW migration will definitively go along with upgrage to CentOS7
Thanks a lot for your help, best,
-Rainer