Speaking of interesting mechanics, if you use Ice Block during Icehowl's massive crash, you don't get knocked back nor stunned and are free to run around for as much time as you want. What always interested me was whether you get killed if you're in the middle of his trajectory.

Last week on 25man coliseum, 10man coliseum, 10man heroic coliseum Icehowl done this:
I iceblocked close to the middle to not get massive crash and he targeted me. I stood in the IB and he stopped as if he hit the wall while I was in it.
On 10man heroic I canceled IB to evo, and I got targeted by his charge. Again the IB was done close to the middle, and I blinked out of his way but he got stunned as if hitting a wall from the point I did my IB.
In the same 10man heroic coliseum a ret paladin done pretty much the same with his bubble and he got again stunned close to the middle even though there was nothing to hit.

I think the mechanic to this is that the player that gets targeted by the charge will get a "circle" around him and will pretty much tag whoever is close, if those that are tagged get in his way they will die and enrage the boss while he will always crash into that "circle" and not the actual wall.

As far as Invisibility spell goes, from patch 2.3 the bosses got changed to prevent vanish/FD/invis to reset combat and start drinking mid fight. So now bosses have a 30-40yards threat pulse which is done like every 10 seconds or so, and if they hit a player the player prolongs the pulse in around 20-30yards. So at every fight in the game if you invis and stay away from boss and nobody from the raid comes near you (except invisible mages) even if hit by aoe (if you don't use any spell/ability/potion/gem/HS/etc) you will survive at end of the fight. The problem is that people see you run and survive, and after a while they will start running after you lol.
Only fight where I didn't survive was Flame Leviathan.

Sorry, I don't have a log file, but here's a World of Logs parse with both me and Zubreil as fire: World of Logs - Real Time Raid Analysis.

A specc including Magic Absorption has been quite "standard" for a long time now I think. Its a brilliant talent in a lot of ways. Ideally, you would want to specc into the talent for any fight where there is some sort of magic damage flying through the air. If you aren't too keen on respeccing a lot every raidnight, then I would definately include the talent in your normal build.

The beauty of the talent is not the mana-component, although that is quite nice (also, can anyone confirm that it actually does react to your essence-based absorptions on Twins? I've been swimming in mana all over that fight...), but simply the many ways in which 80 resistence more can make you survive. Thorim for example is a very nice fight (although easy enough, I'll admit), where resisting a frostbolt or a nova can make quite a difference. Partially resisting Arcane Barrages on Algalon has made a difference between a dead mage and a living mage in quite a few attempts for me. This talent is probably the single-best thing any mage can specc to offset our survivability-deficit we might have against other classes.