From the skills I've personally used my impressions are as follows!
Arrow Spray is very useful, perhaps not for it's intended purpose but... if you use it like a short range 'shotgun' of sorts you can unload all 16 arrows into the same target pretty much instantly killing any target.
Overpower is also quite damn useful on a tank character, means you can instantly strip all armour and knock down pretty much any boss in this version of the game (Bishop may need a melee or two before using it since he has tons).
Infect is terrible, even with a ton in int for bonus damage it very rarely becomes worth using. You might as well just use the source point on something like Acid spores to destroy their shield AND deal damage if not outright kill them.
Steam Lance CAN be useful but requires set up (Which is honestly how all these source skills should be, as a few of them are far too powerful for fire and forget spells) *Looking at you Acid Spores and Chain Lightning*.
Out of all the source skills I would say Overpower, Steam Lance and Arrow Spray are the only ones that are fine. They have their uses but require certain situations or setups to feel powerful, which means you probably don't want to spam them.
The rest are either very pathetic in comparison (Infect) or just outright too powerful for requiring minimal or zero setup (Fire skills, Acid spore, Chain Lightning). You can throw these on multiple characters and spam as their turn pops up to make all fights trivial, (Even in this alpha stage in the first act there are more than enough source points for grabs to make sure a party of four can devastate ANY major encounter with the use of nothing but source skills).
An easy fix for this is to simply make source skills cost 6 AP to use, then buff the lackluster ones to the same level of destructive power. This way they remain a powerful skill that changes the field of battle but now characters cannot use multiple source skills per turn (two since they currently cost 3)'.
