If you want to run a 5xmelee team, prot/ret pals for example , then create a few macros to focus everyones quick heal on any team member:
I give each member 5 macros, which gives me a heal button for each player:
/target player1,2,3,4,5
/cast flash of light
/targetlasttarget

gets better if glyphed and talented.
easy to fire off during downtime/white dmg.
designate 1 member as tank by turning on righteous fury or equivalent and add a few more easy to reach mitigations for that member.. eg, 5 x sacred shield on the 'tank'.
That's just the basics. add in holy prism and all the other good stuff paladins get and its hard to beat.

I tried it with druids and it works to an extent but form switching spoils it really.
works with shamans, burst damage is insane(5x wolves, elementals, totems etc) but much more squishy than paladins due to far less mitigation abilities, and cant use lfg tool! fun though (if you like shamans!)