GL is not the buff that you are in danger of losing.

Twin snakes is a 12 second buff, dragonkick is a 15 second debuff. With a 2.49GCD, you drop 3 seconds of twin snakes every rotation without fracture or HoD will drop dragonkick if you arent millisecond perfect on your rotation. With 1.99 GCD you have zero margin of error for twin snakes and will drop it everytime you cycle in fracture/HoD. This is all unless you skip Truestrike/Bootshing for that cycle which defeats the whole point of using this cycle for dps benefits.