I'll elaborate..
we've had content draught due to last patch overstaying its welcome, and guess what we've been fighting ALL the frigging time in SOO? Orc, mutated orc, orc riding dragons, orc's uderling...
just.. stop...
If Grommash is the final boss for the raid AT LEAST make it count blizzard..
build something up..
something like gul'dan, even while acting as battery is still in contact with the legion, and the when grommash is put in the corner (AFTER TWO RAIDS , PLEASE.. don't make this a 2 raids expac....... it's plain milking your customer for their money's worth) someone important from the legion comes (dunno... archimonde? kill'jaeden? take your pick.. though i wouldn't want sargeras to come and meddle with this), and after someone kills finally (for good) garrosh in the second tier content, gul'dan propose to a sullen and discomforted grommash to take just some "help" from the legion ..
and the final raid is:
1) corrupted orc mage (gul'dan)
2) a somewhat "resurrected" mannoroth or anyway another mannoroth-class demon (brutallus old forgotten brother? something like that)
3) some enslaved&corrupted mix-race brawl-like fight (a-la illidari council//toc "semi-pvp" fight), more demon
4) a natzherim fight
5) a portal overload-like fight, with a portal with some mechanic that will push out every X time a wave of elite demon (between all the "summonable" warlock pet + empowered form)
6) finally fight with grommash somewhat corrupted with some twist, so that it doesn't feel like soo all over again.. in soo, ultimately grom was not "corrupted" by y'saarj, but he was in control... do the other way around, with grommash being first phase, second phase grommash is revelead to somewhat be an empty "husk" for some legion entity and then last part you fight the legion entity with gromm "spirit" (so you somewhat "re-use" the shamanistic component of the orcs) helping you to redeem his misdeeds and the iron horde as a whole..
Of course feel free to add content as you see fit, but after having
1) mantis/mogu first tier content of mop
2) troll content second tier of mop
3) orc content third tier of mop...
making the LAST tier of drenor again orc-centered will feel like a slog.....
Feel free to disagree of course community, but i think we DO need some variation in order to avoid a SoO 2.0 in drenor....