It wasn't a big deal when it was 5% haste per stack, because a "JV > Wake > JV" opening during Sanctified Wrath meant 50% haste, and thus much faster HP generation for the rest of the duration.
In contrast, now "JV > Wake > JV" gives just 20% haste, which whilst nice, is only 40% of what it used to give, and makes generating the rest that much slower, which in turn means you get less time spent at max stacks.