Y'Shaarj will be.
They always make another boss as filler for the time it takes for them to make another shitty expansion. This isn't even a prediction.
I think Y'Shaarj will play apart. Just not sure in what capacity. Most likely whatever Garrosh is going to do with the Heart, will get out of hand and cause more damage then good (for Garrosh).
But hey, I´m sure they will come up with some idiotic filler boss like before cata that made no sense whatsoever.
"Only Jack can zip up."
The word you want to use is "have" not "of".
You may have alot of stuff in your country, but we got Lolland.
Y'Shaarj is already dead. Garrosh will be the last boss, and to be fair... I hope Baine takes him down!
Well... The majority of expansions have ended with an extra filler-raid after end-boss was dead..
TBC: Illidan was always meant to be end-boss, but Sunwell/Kil'Jaden appeared out of nowhere..
WotLK: Lich King was always meant to be end-boss, but Ruby Sanctum/Halion appeared from nowhere..
Cata: Deathwing was always meant to be end-boss, but after raidig him for months and months without end, we all yearned for an additional boss, appearing from nowhere.. Unfortunately, it never came.
MoP: ......we'll see...