The wording is kind of funny, but it seems like what they mean is that an ilvl squish to ToC gear will passively increase the difficulty of ICC.
"iLvl squish for T9/T10/S7/S8
The proposal of reducing the iLvl (and in turn the stats) of items from ToC and onwards (That is T9, T10, Onyxia, Ruby Sanctum, S7 and S8) was made.
The stated goals of this change were as follow:
- To give more relevance to Ulduar once ToC is released.
- To increase the difficulty of ICC by reducing power creep.
Furthermore, this change would also reduce power creep and gear disparity in PvP for Season 7 and 8."