So as Ion mentioned on the panel above, Tomb of Sargeras will only have 9 bosses. For a full fledged tier, that's a very small number, in fact, last time we had tiers this small was in Cata, with Firelands at 7 bosses and Dragon Soul at 8, and I think it's quite commonly agreed that Firelands was rather short and Dragon Soul was a disaster.
Cata Tier 1 - 13 bosses
Cata Tier 2 - 7 bosses
Cata Tier 3 - 8 bosses
MoP Tier 1 - 16 bosses
MoP Tier 2 - 13 bosses
MoP Tier 3 - 14 bosses
WoD Tier 1 - 17 bosses
WoD Tier 2 - 13 bosses
Legion Tier 1 - 20 bosses
Legion Tier 2 - 9 bosses ?
There is more than just that, if we keep the 6 tier piece format, then at least 6 of 9 bosses are bosses who drop tier sets and that just doesn't feel right to me that 2 out of every 3 bosses should drop tier.
Do you think they plan to add more smaller instances like ToV, seeing as it was a relative success with the community? Any raid with 9 bosses must inevitably pale in comparison to the 'gold day raids' like Throne of Thunder or SoO.