That actually won't change the relative power difference between fresh 100 and end-of-WoD tier fully geared toon. Only the ILVLs from 1-90.
- - - Updated - - -
ILVL inflation is totally deliberate, at least in the context of current content. You're supposed to feel much stronger when you upgrade your gear to the next tier, otherwise it's lame.
It's just the accumulated inflation of 5 eras of WoW that's causing the numbers to be downright silly.
- - - Updated - - -
That was more class imbalance/bad PVP design.
- - - Updated - - -
Again, this is related to the number of "tiers" of gear. TBC only had one level of difficulty per raid, Wrath had three (10 NM -> 10HM/25NM -> 25HM). Cata only had two (NM/HM) at least until DS where LFR meant it had 3, MoP had 3 but also had ILVL upgrades and T/Warforged gear.