Guild Wars 2

I only care about dungeon DPS output, and I run with a warrior 98% of the time. Would it be best to go for all Mighty Infusions since my crit chance (56% unbuffed) is already decent when topped with buffs, or is it better to have a mix?

Would mixing it even really do anything, or is it pointless if not investing a lot into a single stat?

Cheers

If you consider targets that are immune to crits (e.g. burrows in AC or world bosses) obviously power infusions win.
If you only consider targets that can be hit critically, the answer depends on your total stats at that moment. I have prepared a small spreadsheet to demonstrate this, which you can download at: http://we.tl/pYHZErXilb (for the next 7 days).
Just fill in the power, crit chance and damage (green colored boxes) and you’ll see how many precision infusions give the largest dps increase.
You will also see that the difference between all precision and all power infusions is not very big.