Mandatory? No, they’re not. It’s a classic version, gameplay-wise close to the original game, with all its pros and cons…and a certain disbalance is always present. Similar to how let’s say protadins / hpalas were OP in Wrath, BDKs are now and MoP will quite sure have anothers. There will always be classes that are just stronger than the rest, and you could ague that the difference between best and worst should not be that big, but…check out dps charts from later WotLK stages (let’s say ToC to not have brutal dps on rets, furys and cats) and the difference between best and worst…and not nearly everything was “balance-patched.” It just didn’t feel as bad because there are a milion of dps classes, so the scaling goes more smoothly, while with only 4 tanking classes, the differences simply seem bigger.
Didn’t say or at least didn’t mean that the other tanks are dumb “spam one button” arcane mages of WotLK, but considering that all the other classes have mastery that works passively, while the DKs rely on DS, which should be planned, and that the BDK still has more CDs to use (and quite often they do need to be used), I stand by my original statement - which you of course have no obligation to agree with.
Also, you say that if you have some basic class knowledge you can tank raids - well, the way I see it, tanking in cata is in absolutely no way about the aggro, as it used to be in previous expansions (just taking expansions as a whole since we’re all on classic, which always runs the latest patch balance), but rather more about the knowledge of the fight, needed positioning, CD usage and so on - so yeah, I even agree with you on this one, I just don’t think it’s wrong. And yeah, if you only tank normals…it ofc depends on the PoV, beginners would probably find some bosses complicated too, but I’d say that normals are actually supposed to be very easy, or at least they’re made that way intentionally - and no, I don’t really know why the LFR difficulty was introduced, DS bosses are easy on normals too. But stating that basic class knowledge is enough for raid tanking - well, if you’re talking normals, I think that’s deliberate, it’s the HC where you need to be on higher lvl. And I think this goes for all the tanking classes (got experience with more than one as alts).
Again though…the question here doesn’t have THE correct answer, so we sure can agree to disagree