If you have the right 7* toons with the right mods/gear level a heroic raid is easy to beat even if only a few of you have full teams. When my guild started doing Heroic Rancor only a handful of us were able to do enough damage to finish it in time. As long as the other members have at least one 7* toon they will be able to get rewards even if they don't do any damage. Try having your more powerful members specialize in a specific phase like we did until the rest of your members are able to contribute significantly. I personally run a team that's totally F2P and solo phase 1 and do about 10% into phase 2. (L)Teebo, Phasma, Chewie, QGJ, and Yoda. If you have Teebo and QGJ potency high enough you will constantly doing TMR.