Is it something I said?

How do you keep the caster DPS from "following" right behind a tank without overly complicating your control setup?
How are those of you 5 boxing setting up your dmg/healing spells? Only the best one or 2?
Skipping over things like iceblock or blink?
Im fortunate enough to have 2 mages and 2 shaman so not a lot of variation in spell types, but what would be an efficient way to have one shaman be tankish or at least most high agro, one shaman mostly healing and the 2 mages hanging back casting?
Should I limit each toon to 5 or 6 spells regardless of role and then separate them by toolbar? It sounds simple, but what if I need the healy shammy to dps and the tank shammy to heal? I'm just wondering if there is a "simple" solution, because the only thing coming to mind is using modifiers for every spell I have, and it just sounds too complicated, like there has to be a simpler route to take.
I see all the posts about your various 5 man setups, but not how you make it easy on yourself to have 3 distinctly separate roles within that group. I'm just lookin for suggestions to get me headed in the right direction please.