Both snakes and conflags were reduced considerably. The number of pug groups clearing after that was pretty considerable from my loner FC mates. Echo did make a difference, but tearing down a DPS wall and the snake timing due to HP made tremendous changes.
People running up against a wall for the meteors/golem will probably get similar relief. If PUGs no longer have to blow an LB for instance on that add during Heavensfall then it frees it up for slapping Nael down that much faster. Anyhow, the adds changing is always the easiest nerf imo.
I would think just removing the lockout would have effected things more dramatically than the snakes having a little less HP. No lockout means, more groups running, more experienced people joining up with learning groups and telling them how to get past the last few hurdles, etc etc and so on and so forth.
I mean, again, those snakes were being dealt with identically before and after 2.2 hit. We tanks would gather them all up, they'd be caster LB'd, then the party would finish off the big snake. I recall no real change to mechanics, so at most that might have provided some extra cushion for the transition into the twister phase, which is no big deal, seeing as that's a fairly easy transition.
Conversely, after 10% echo, a lot of groups stopped LBing the snakes entirely, and saved the LB for Twintania.