Well the thing is... Whatever the intent has been/is at the moment, I have experienced exactly what you describe in regards to the 4 hits and done with Sparking Swings during my first playthrough, testing the skill around level 10 and onwards.
NOW, on my level 6 character in Fort Joy area I just tested it. Setup:
I cast Sparking Swings, I am dualwielding. I did nothing but basic attacks in the fight with the buff on, for testing purposes. I was hasted. I did a total of six basic dualwield attacks, hitting twice with each 2AP spent, both individual hits procced individual sparks that hit a nearby monster. All six attacks procced sparks for a total of 12 sparks, and I still had the buff running for the last round to come (the fight ended at that point).
So I am in fact experiencing at this very moment the skill behaving exactly like the tooltip is saying, which mind you I have not experienced earlier.
Oh and I agree 100% with your assessment of the hybrid builds, I like them and use for great effect (I play only on Tactician, and I feel they are not at all lacking)!
Last edited by Sokerimuro; 15/03/18 10:31 PM. Reason: Typo