What they should be doing (pardon the rudimentary MS Paint skillz)
Their plan leaves 7-10 PvE in shambles because the size of Tier 8 is still too large and the gap between Tier 6 and Tier 8 is also still too large. It kind of looks like they're not considering SpecOps in their plans, and SpecOps breaks at Tier 8, not at Tier 6. Right now it's pretty rare to see a Tier 6 in a Tier 8 match, but it does happen and those poor Tier 6s are useless when it does.
My idea is that Tiers 7-9 should be the same "size", but smaller than Tiers 1-6, and that the gap between odd numbered Tiers (or even numbered) should be the same progression as it currently is in Tiers 1-6. That will mean that the top end advantage of Tier 10 over Tier 9 is smaller than they have planned (which IMHO is good for all game modes), and perhaps more importantly the gaps between top-end Tier 6s and top-end Tier 8s will be smaller (good for SpecOps), as will the gap between top-end Tier 7 and top-end Tier 10 (good for PvE and presumably GLOPS and PvP).
To do this, top-end Tier 7s get nerfed. Bottom-end Tier 8s get buffed. Top-end Tier 9's get nerfed. Tier 10 gets nerfed hard - its entire new range is below the old range.