Next to nobody right now is testing hunters' focus regeneration in MoP.
This is because just about everyone and their mother has the tier-13 two piece bonus. That bonus completely (completely!) changes focus regen. I'd say a reasonably large number of hunters participating in MoP have the four piece bonus. That 4pc bonus is like a little heroism/bloodlust. Focus regen is through the roof during those periods.
When various class mechanics are polished and testers are in the home stretch in level 90, hunters will experience an "Oh! Wait a minute here now." It will be an eye-opening event. I fear that may be too late for Blizzard's taste to put another coat of polish on hunters.
Pre-tier-13 we would gather the extra focus by aspect-twisting to Aspect of the Fox for greater focus regen and twisting back for all true damaging shots. This was from the One With Nature talent. But I've never been a fan of aspect-twisting and that talent doesn't exist in MoP.
Next on my list... trying the new Pre-made Panda Hunter. Hopefully I have enough copies left.