If you are Ally you can control a shaman and have 3 ret and 1 prot. I have a lot of fun now NOT controlling the tank. While sometimes I wish I had some more flexibility (read totems) I wouldn't take a holy paladin. I have a 4 ret 1 prot team, Divine Storm provides very consistent passive AoE healing. In instances any of your Rets can heal in a pinch, but a tank eventually becomes essential.

As far as the running around in circles, if you have a high threat tank, you don't have to spam the interact target as much because the mob anchors to the tank, then you can control your toons placement as you will with less running. With an all melee team you will still see it a bit in my experience, you get used to it.