Its ffxiv combat really so slow and boring?

[Daemic]

Combat is boring because it's a stagnant, static skill system: each player has the exact same skills as others of that class. There's no variety or creativity like in build-based systems. The simplicity is mind numbing, and rote memorizing the "optimal rotation" of your tiny pool of abilities is the opposite of enjoyable.

At least healing and tanking is a dynamic enough experience to stimulate some brain function.