I have this Pally/Priest/Shaman/Druid/Mage team except my priest is holy spec. Click cast sequence macro's are a must for max DPS. Also a good idea to have a basic no-dots cast button to conserve mana as well. The druid will be out of mana at all times until level 40 as balance. All instances are doable, but the pally tanking will be annoying until mid 20's when you finally get enough specials to keep off of cooldown.

As far as PVP goes 5v2 is doable but 5v3 is hard. It is especially hard for the priest to keep herself alive with more than two beating on her. Hopefully as disc things will be easier in that regard. 80's will tend to gank you, but most of that can be negated by not trying to mine while leveling (.... but I do it anyways). Not sure how viable a team like this would be for end-game PVP. Either way its still a nice change from the cookie cutter pally+4xshammy team.