Gunsetsu is FINE, probably the best legendary shown so far.
Good as a 1 of for those games where both sides exhausted their resources or if your opponent bricked didnt draw their orchis, kuon...etc and is saving their Sevo for their big boss card this pretty much FORCES them to act and respond to.
And doesnt require evo which is nice, it just furthers the idea that abyss should be using up evos like candy to help them deal with everything in the early game.

Which is good.
Abyss just needs more early game support.