We downed Lost Island Saturday in under four hours. Brought the same group in on Sunday, and the crap was no different. We needed too much luck, even with our exemplary skill and already-tested strategies, to make it through, again. It is too buggy, there are too many overlapping BS mechanics that punish melee, and too much blind luck is needed to make it through. Why? Cause we had one melee DPS. That's the only difference between you and me.
Hell, we even had one instance where the pillar boss randomly did twice as much damage the entire fight, no reason, just a bug. Even with two people healing, we could not keep up. Went back, did it the next time, no problem, breezed through it.
My group (Op healer, Sorc DPS, Assassin DPS, Jugg tank) originally took 3-4 hours to beat LI, then we tried it again one-shot the whole thing in 40 minutes.
It's not luck based, there aren't any glaring bugs in it. We did it just fine with a melee DPS. Stop complaining.