Alas, that might not be the case.
Trial of the Crusader has five boss encounters, but if you want to, you can count it as many more. Northrend Beasts alone is four bosses, Twin Valkyr is, well, two. I can't seem to find a definitive number on faction champions but it's safe to say that those are at least five. That would make Coliseum a 14 (or more) boss instance.
"players have visions of the DK who parks outside of Icecrown until boss 4, 17 and 31 (yes, IC is that big)"At that rate, Icecrown would only have 11 boss encounters - which would clearly be another disappointment. To be fair, the truth is probably somewhere in between. Other raid instances have had the same effect but not always in the same magnitude. A very high number, like thirty-one, is suspicious however - especially given the recent history of lazy content development. If it's a typical instance, the real number is probably around 20. It could be much lower. Don't get your hopes up on this impressive number of thirty-one, it may just be and likely is, a fluke. Or a publicity stunt of the "mounted combat" kind. Sure we got mounted combat, but not as some expected it and not in a very good implementation.
GC if you read this (yeah right, who am I kidding) - if this is real, please tell us that we will get thirty-one unique and non-exclusive boss encounters. Until then, I don't buy it.
UPDATE: Apparently the whole thing was a joke by GC.
"Then in an example on how we don't want raids to rotate in tanks, I wanted to pick what I hoped was a ridiculous number so that players wouldn't try and and deduce from my answer how many bosses Icecrown has."
I'm sorry GC, but if you want to make up a number so high that it is ridiculous, don't follow it with "Yes, IC is that big".
