Alliance Raids: Does anyone follow mechanics or it just bull rush?

[Frizze]

As the others said, this isnt quite as big a problem as your one run would indicate. I am sorry that no one was really explaining things as you went, but LotA doesnt have much to it and the item level sync leaves everyone powerful enough to eat a lot of mistakes. The boss mechanics as i remember them for LotA...

Bone Dragon - Fight him toward the outside of the arena. The first two times he dies kill the adds that try to run to him. Most tanks point him outward, so he might have a cleave.
Atomos(not technically a boss) - The groups split up into 3 paths. Try not to pull early, because if the arena gets locked before people show up the system doesnt send them to the proper lanes - can cause wipes. Get 4 team members to stand on the button to open up the next teams boss(one of them should be opening yours). Have someone pull the adds back to the people stuck on the button while the others focus on Atomos.
Thanatos - The boss can only be hurt by someone with the buff from the Magic Pots around the outside. At the start of the fight they mark up alliance a, and just before their buff fades alliance b gets marked(etc). Those buffed can just focus on the boss. The rest of the raid should focus on the adds that will be trying to destroy the Pots.
King Behemoth - Main mechanic is ecliptic meteor. Small rocks will fall from the sky. Stand with them in between you and the boss to avoid the hit. Note: If you are inside the bosses hit box the rock wont save you - so if you get marked with a falling stone make sure youre at least a little bit back. The adds will try to break the rocks and otherwise be a nuisance, so an offtank can corral these to make things a little easier.
Phlegethon - His main aoes are obviously telegraphed. The big mechanic is Ancient Flare. When he starts to cast it everyone needs to run out of the central arena and stand on their groups trigger. If enough people dont get there the shield doesnt go up and everyone wipes(one group failing wipes the raid).

Thats more or less one important mechanic per fight, a few of which are basically cheesed by doing too much damage. As the others pointed out Syrcus Tower(the 2nd alliance raid) has some of the same tuning issues and even with everyone ignoring mechanics most of the fights are too easy to wipe the group(the last 2 fights are the only real dangerous ones). The mechanics in the last level 50 raid must be at least somewhat followed or everyone dies(each boss fight can go poorly if no one wants to play along - a couple of them spectacularly so). The first level 60 raid mostly has mechanics that hit hard or give vulnerability up stacks, so some of them get skirted a little. Everything after that requires a good portion of the raid to pay attention and do it right. So try not to be discouraged too much, these fights get better.

[Vidu]

Bone Dragon - Fight him toward the outside of the arena. The first two times he dies kill the adds that try to run to him. Most tanks point him outward, so he might have a cleave.

He does - a quite nasty breath in front of him that will give you the "disease"-debuff (is it called that in english? the thing that makes you slow but isnt heavy). He also has a frontal cone AoE. Its also just a tank habit of basically poiting everything outwards, which is the safe way to go.
The Bone Dragon has the habit of just running away from the tank randomly, even though the tank didnt loose aggro.

By now he mainly has the habit of just dying for good though, with no one having to deal with any mechanics.

Any tank who wasnt the MT used to be in charge of pulling the skeleton-adds to the outer platforms to create maximum distances between them and the boss (when they touch the boss, the whole raid will take damage, so that was to be avoided). Normally it ended in aggro-fights over the adds, so I used to just have a cup of tea during this fight when it was current content...