I made a very similar team, Pally Priest Shaman Mage Druid. I played them together, and it worked well. when I got a DPS meter, I Noticed my Druid (eventually going to be a moonkin) was last on the DPS list. He was really only casting wrath and starfire. When I switched him to kitty mode, he did much better, but was a tad harder to control (I never got around to setting the macros for the cat action bar. I will keep him in cat mode (except to off heal) until he gets moonkin form. My Mage always pulls aggro, but my pally just recently got consecration so that should help, and once the pally gets geared, threat shouldn't be a problem. I still need to work out my healing macros on my priest. This is also my first attempt at any class beyond lvl 10. I only have a 70 paladin right now, so I'm learning all the other classes as I go.

Some thoughts. DPSing is easy enough with macros. I just put similar cast time spells on the same hotkey. I have a "long" and a "short" button, so i usually start off with the long cast, (mages "long" is really long, so I can get off a short or two before the mage finishes, helps with aggro to) My issues with healing comes from the priest having sooo many healing spells compared to a paladin. Paladin healing is simple, quick short, mana efficient heals (called whackamole by someone in another thread) and long slower big heals that kill mana if you do too many. Priests have HoT, AoE, long, short, etc etc. I'm beginning to wonder if I should swap out my priest for another paladin as healer. Lack of AoE heal might be an issue, but I was thinking of setting up 10 buttons, with a small and a big heal for each character. I will probably get an xkeys pro, and have one section for healing, one for tanking and a big one for dpsing. With those hotkeys set up, I could also add a /cast [target=party1targettarget] Holy Light for bosses and smaller packs of mobs (large mobs would get too complicated) I will definately be trying it both ways (paladin vs priest as healer) I want my tanking and healing to be the part I focus more on, and the DPS to be something I just button mash...

Meanwhile, I am leveling a paladin healer and 3x warlocks, and ended up leveling them more, cause i wanted a second paladin to boost chars on my main acct. I'm gonna use the 2 pallies to boost different combinations of characters so I can experiment, and or swap out for different situations. Ideally I want to be able to farm Heroics and even do Kara with 5 more people (or another 5 boxer on the same server) Having a diverse set of characters will help me a lot I think (off tank for certain encounters, off healer for others, Attumen/Maiden respectively comes to mind) It's definately easier to level 3x of the same DPS class, you just clone everything they do. It is less fulfilling tho. Playing with an "ideal" 5 man group lets the experienced player be more versatile, and more powerful. I won't run into issues where certain immunities severely gimp me. I do damage of all different types, I have multiple rez/healing options, etc etc. Ultimately, for PvE at least a diverse 5 man can be the most powerful force there is. 5x shaman is still probably better for PvP in the Arena, because of the hybrid nature (palamages )