Ok - aside from my whining about how this personally impacted my gaming plans, here are some business thoughts (i posted these on the blizz thread as my main Dalean).
This is a classic mobile app "timer/soft currency/hard currency pinch" monetization model.
The timer in this case is the "time to level", which has been made more onerous by increasing XP, increasing mob HP, decreasing RAF bonus, nerfing Heirloom items, and capping total XP bonus.
Players can bypass the timer through either soft currency (grinding time to level), or hard currency and spend $$ for a boost.
The irony for me is that most people who will want to pay for a boost would do it if the grind time were 15 hours (pre 7.3.5, full RAF, full pre-nerfed Heirlooms, level 110 booster, no XP bonus cap), or the 45-70 hours it is now post 7.3.5.
Further, in mobile apps this model works because they have no monthly recurring fee, so if they don't pinch the player to make a hard currency purchase to clear a timer they get no money - so literally the developer has nothing to lose.
Here, if the pinch is too hard, you will "leak" paid monthly subscriptions at some percentage (even if it isn't high, every 4 months lost subscription cancels one boost revenue event).
And as I said above, I cant see this pinch actually increasing the number of boosts by that much.
Additionally - RAF has nearly no value. And that is bad for Activision since RAF was a way to entice more players and monthly subscriptions.
I see activision bleeding some small level of existing accounts (not large, but enough to erode any boost revenue increase) and canibalizing future revenues from RAF for current revenues from boost.