No secondary stat has much impact right now. But that doesn't mean you can gear for specific gear. It's really questionable whether crit is really worth it or not, but same goes for determination. The only spells that really benefit from a big increase (regardless of overhealing) would be Aspected Benefic and aspected Helios in Nocturnal Sect. Whereas determination helps every single spell you have - Be it mitigation, DoTs or HoTs - regardless of your stance.

I'll repeat it again: Stats don't have much impact or value with current gear limitations.

Other topic concerning statweight:
http://forum.square-enix.com/ffxiv/t...highlight=stat