Barrage, Speed Infusion, Energy Orb, Stun Mastery

Energy Orb - 900% Damage to six monsters, when the damage halves per monster. It's a charge skill. Dragon Strike does 810% per monster and is not a charge skill. What makes Energy Orb the least bit desirable?

You have to have your energy charged, meaning you have to be in the bubble. It doesn't have to be charged like Screw Punch. But yeah, it's not very desirable.

Stun Mastery - I heard this skill doesn't add 60% to your overall damage, but has a chance of adding 60% in the sense that Dragon Strike would do 870% opposed to 810%. Is this true or did I hear wrong?
I also recall seeing a video with a guy having Level 1 Barrage with Sharp Eyes (I assume). His regular hits were doing 2k-3k each, but his crits were doing over 10k. How is this possible?

The example you gave is how all crits work: they add a % damage instead of multiplying your damage. The video you saw was likely with a low level Barrage (say, 100% damage or so) and he had SE. So his crits were doing 300% damage. Devil gave a good example of how this works.

Also, think of Barrage as 10 hits, not 6. The first 4 hits are 1 hit each. The 5th hit is actually 2 hits added together, and the 6th hit is actually 4 hits added together.