I can only talk for PVE, as I have next to no experience in PVP.

Very good team, with a lot of synergy. I second the removal of the resto druid (doubles up on MoW and the 6% extra healing) in favor of a Holy (disc could work too) Priest.
For the last spot, mage and lock are both great choices, but I prefer the mage for free ports and water, they save quite some time.