There's a couple of us that box on alliance side on whisperwind. pretty old server though so it can be kind of crowded at times. incidentally the only other multiboxer that i talk to and am friends with is on horde side. *wave @ oz*

also, i have an similar setup as yours though i usually mix and match a mage into the warlocks slot and use the warlocks on a different team. Can assure you that team will work out fine for heroics at least. though on certain fights when i'm not paying attention, the priest is kind of squishy and i had far easier times gearing up my other alt teams that had:

pally healer (not as hard to box or as inefficient as other people thinks, but does require individual heal keys setup for each party member to work well with beacon of light),

druid healers (super efficient. almost never ran out of mana. lowered CD on innervate makes it stupid easy to be fm constantly otm, but ae heals are kinda meh. again; requires individual keys setup for each characters on the team to make ae heal scenarios go semi smoothly),

shaman healers (one of my favorite healers for my teams when i began. 75% of the time she just throws out an earthshield and dps since that's all that's needed esp if healing stream totem is also down)

but i love my priest healer for pvp. being able to spam an adequate ae heal like holy nova so the opposing side cant lock me out of my healing school is critical.

as for racials, i guess it depends on if you are purely pve oriented, or if you ever have desire to do pvp like in BGs or something. i prefer a human team for pvp just because of trinket racial so i can save that slot for other burst dps trinkets so i can steamroll opposition faster.

good luck with whatever you decide and if you start a team on whisperwind, let me know