I have in some points a different view but in the core I agree with you - it is boring. I finished yesterday with the main story as it needed so much to stay motivated enough to follow the endless scripted quests.

For the quest: I experienced one time a boss I could not defeat as somehow I made no damage. I restarted the game and changed to the Naru Gear that comes with the story line. The second try then worked like a charm. My impression is, that the story line bosseses are easy-peasy as long as you use the standard gear. If not, there are big chances that something is just bugged.... It is not so rare that for some reasons ever there are chances you make absolutely no damage.