got to love ToW and moonkin aura

as said before 16% to spell hit is what you should aim for (having 12% already is a great start). I'd hesitate to say that you should try taking some of the talents giving you +hit as you are very likely to get those last 4% from gear. Also don't forget that +crit means mana efficiency on you shamans. If 50% crit rate is attainable then that means you'll be casting cheaper Lightning bolts nonstop.
as for optimising dps, I'd say it's likely with such high +hit and crit that Spelldamage is going to benefit the team more once you hit the 16% hit cap. It's rly up to you.. personally I just love the idea of criting like a maniac take a guess what i'll be going for :P