If your healers are always on top of things it's conceiveable to beat Titan with something like 2000 HP if you always dodged every dodgeable mechanism. There's also no reason for any random guys to believe you're capable of this, and even if you are, a lack of HPs implies a lack of DPS which makes the fight longer. Even if you can be 100% you'll never screw up, your healers might eventually miss a heal for whatever reason in a prolonged fight and obviously if they mess up at all, you're going to die horribly to Tumult as you lack the HPs to survive it. I mean sure sometimes I see these super awesome guys that can seemingly dodge an AE forever with equally awesome healers, but forever is actually more like 5 minutes. If you ask those guys would they like to continue this sequence for the next 30 minutes, I'm pretty sure they wouldn't want to do it because there's just a very good chance you'll screw up at some point and make an unrecoverable mistake.