If you aren't gonna have a tank, dont get mages for aoe. I run a prot pally Holy priest and 3 mages, so my mages rarely get womped on (when they do they die fast) I would just go 5x boomkin if I were you. I guess the 2 druid 3 mage could work if you made one a bear tank and one resto (or ele/resto, or full ele if you prefer) and with dual spec u can have 5x dps, and a holy trinity for instances.