If you 4hko windraider with 11 blast, you would most likely 3hko them with maxed blast.
Edit:
Also I'd like to point out something about the 3rd job build.
Sharkwave should be maxed before seriously adding anything else. 1 point in spark/critical/transform/shockwave wouldn't hurt, but stopping sharkwave at 21 isn't the best idea. From 21 to 30 it's a 45% damage increase, and takes 9pts. While on average, it's only a 40% increase with maxed critical, and that's 20pts.
Spark aren't that great either, it's not as simple as your damage*120%, sometimes I hit 1 with it. Generally, the damage is very unstable, and not that much noticeable. Not to mention it makes you use extra mp everytime you attack.
So to maximize killing speed, max sharkwave > max critical > max spark would be the best route to go.
Edit:
Also I'd like to point out something about the 3rd job build.
Sharkwave should be maxed before seriously adding anything else. 1 point in spark/critical/transform/shockwave wouldn't hurt, but stopping sharkwave at 21 isn't the best idea. From 21 to 30 it's a 45% damage increase, and takes 9pts. While on average, it's only a 40% increase with maxed critical, and that's 20pts.
Spark aren't that great either, it's not as simple as your damage*120%, sometimes I hit 1 with it. Generally, the damage is very unstable, and not that much noticeable. Not to mention it makes you use extra mp everytime you attack.
So to maximize killing speed, max sharkwave > max critical > max spark would be the best route to go.