Galio Q should do slower tick damage.
Adjust the damage as needed to keep it where it needs to be to be fair, but it ticks too fast. It's the only skill I know that will proc a thunderlords in 1 skill, aside from maybe singed but they don't usually use that anyway. If you're in the center even with dash skills it will proc most of the time, it only requires 3 hits so the one cast initial hit, the immediate tick and then the 2nd 1/4 second tick makes 3. It's just too fast. Lets be reasonable here, force him to actually have to use other skills to produce a thunderlords.