Do you have armory links for your tanks (it'd really help more than just the hp)? Do you guys log anything on world of logs? Reviewing that would help as well.
Given what you posted...
At first glance, that warrior with 5k GS is very low on HP for a buffed tank given that 5k GS usually means you're in ToC gear. He may be overstacking avoidance. I find it odd that the druid would be the one needing spam healed given the stats you listed.
We run 7 healers on that right and drop down to 6 for the rest. Running 2 pallies or druids that fight helps a lot with beacon and hots.