Shaman's Stats: Cons, Int, Dex?

Dochitha

I have always think Shaman should prioritize CONS. While INT affects bleeds and throttle, it does not give as much benefit in PvP whereas CONS allows a Shaman to tank easier. I am not sure about DEX...as it is mostly avoiding physical attacks...

What is the most important stat a Shaman should look at?

Tael

You essentially answered your own question.

For 1v1, con is far and away the most significant thing. The extra damage you get on your damage abilities from more int is unlikely to allow you to kill many more people and you could almost certainly just kill those people with something other than a damage strategy anyway. Mana is always useful to everyone since it means more clotting and makes cath/absolve/aurify harder, so there's a little extra incentive to take int, but only slightly more than for most other classes since you can blow through it relatively quickly - but I think few people of any class prioritize int for the larger mana pool (though I know there are some people who do).

Though it should be pointed out that, even though con is the only stat that doesn't have mechanical diminishing returns, it doesn't actually have linear returns in practice. A lot of damage in Achaea falls into two categories: a sort of base level (a knight or blademaster or monk's constant damage output for instance) and a big spike intended to work as a kill move (things like BBT or DSB). Once you have enough con to manage the base level reasonably well without it interrupting your own strategy too much, you don't gain as much from marginal increases that leave you still able to survive the basic damage, but still just as vulnerable to the big spike damage.

If you primarily bash, there's an argument for some int since it scales your bleed and killing things faster is usually desirable (and, when it lets you kill things that you can't tank indefinitely before they kill you, increased damage is functionally equivalent to being more tanky while also killing faster).

If you do mostly group combat, I suppose that higher damage on throttle and bleed might theoretically be more useful (more useful than in 1v1 anyway), but higher con is also pretty nice for group combat so it takes more newbies mashing their bashing button to kill you.

Dex is probably not worth it. Usually, people only go dex because their class forces them to (serpent) or because they get some very large bonus to dodge like weaving or acrobatics (though fighting mounted can help with this, people can respond by killing your mount of dismounting you). Even then it's a tradeoff - it leaves you better off against some classes once you have a dodge chance high enough to really slow down their offence, but does absolutely nothing against others - and your dodge chance just isn't likely to be high enough to really slow down anyone's offence without some ability to amplify it.

Grandue

Strength. 

Helps with fishing and pumping iron

Sena

It doesn't help with fishing any more.

Grandue

Well, pumping iron then. You don't want to be the shaman with stick legs. So embarrassing. 

Comitis

Find a good balance between con and int. Con will help you tank while bashing too. While int will provide mana and spell power. Basically. Find a spot you like.