Im in 485 ilvl gear at the moment and even reforged all Haste I can't meet the 5,273 Haste cap. Im reforged Haste and gemmed Crit and currently around 4,670 Haste. Should I gem pure Haste instead of Crit to meet the 5,273 Haste cap or just flat out gem/reforge all Crit till I can make 5,273? Hopefully that makes sense.
Could you possibly link your armory?
Without any armory data to base myself on, I'd say that yes, you're probably better off replacing 2 yellow crit gems for haste ones.
Unless you have the Tier 14 4set, I'd suggest going for the 5273 haste cap. That's what we did in MSV with lesser gear, why not do it now? You should get the haste cap by default soon unless your gear is full of crit/mastery.