Then provide proof of the berserk/enrage timer from either tbc or wotlk.
But its okay to be dumb and not understanding that every boss does not have a enrage/berserk function built in and instead sometimes have soft enrage mechanics built into the fight. Guess you never actually fought Kil'Jaeden and just used the first video you found as a reference and pretending to know stuff.
For Kil'Jaeden that one being
http://wotlk.cavernoftime.com/spell=45657
Which in wotlk is trivial as you can tank trough it on pretty much any class above 5k gs.