TBC was first created to expand the Classic game. When playing a TBC server can allow you access to WOW Classic TBC Gold all Classic content, even though it's now obsolete. They are currently considered separate games for those who prefer the vanilla/classic version of the game.
Wow, classic is dead. I'd suggest tbc to anyone who would like vanilla. Are you a brand-new player? If so, I suggest that you go with retail instead. It's more refined, and has a number of enhancements to your quality of life.
Mobs with trash right before boss come with a buff that they apply on themselves that increases dmg by about 10%. You can then kill them until a spell from a mage steals 8-10 stacks. After the mage has at least stacks take out the boss and allow the mage to remain in the blue beam for the duration of the phase. Invoking all the innervates and tides you can while healing the shit out of the mage too. Arcan gets to these numbers flame and frost around 5k to 5k.
My friend, who is a healer and tank, and I run heroics. We'll carry the dps for so long as the boss can be hit (level up to level 73 boss). There are dungeons in which it's possible to have an issue, but there are numerous heroics in which the issue isn't that important.
Yes, it did happen once. We managed to buy WOW TBC Classic Gold save the run. A belt wasn't worn, but it was an effective chance to save. As long as you've managed the adds , and you've got an excellent health shield, you're usually safe. It's not easy to save adds when you've been careless and let them go.