So maybe to alleviate the disparity between tank and healers versus DPS, they need to crank up the DPS gear drop rate to twice as much. Then the healers and the tanks will have to run the dungeons many more times to finish gearing, whereas the DPS can run it once or twice and be set!
Or more and more decide not to be tanks or healers.
People don't decide to be tanks or healers instead of DPS because of gear drops, or vice versa. (Invites? Yes.) It's because the two roles tend to attract certain mind sets. Tank types love being the hero, being the one to protect others from the monster, and gain their satisfaction from keeping everyone alive in the end. Healer types prefer the support role and helping the party perform as smoothly as possible.
I tend to gravitate toward healing and support roles in MMOs and will stay with them despite the crappy lack of gear drops. (Mage gear really doesn't drop that often in dungeons...)
Back when we kept records in Dynamis in FFXI, we were not suprised that the #1 gear drop we received was the utterly completely useless WAR mask in Windurst. We got five of them in a single run one day even before they adjusted the entire system. It wasn't just a psychological "hey we seem to get a lot of these things" - no, we really did get a higher than average number of it.