I don't think Graces story is boring. Duckroll just hates Tales games and finds excuses to stop playing them even when he's having fun!
Graces story is good because it doesn't try to be anything beyond generic and simple. It doesn't think it's smart and doesn't shove it in your face. It's not like most Tales games where you groan and smack your forehead.
Otoh, there simply isn't much to it. The world is tiny (3 cities), and the plot is one note (go do ___ from city to city). There's a little more to it, but there are hardly any twists in the game and it's not particular long or epic in scope. It's a simple rpg about a bunch of characters going around the world saving it, the end. But it's accompanied by the most fun and best battle system in the series, good dungeons, and fun gameplay sub-systems. The game is fun to play and the story is enough to simply give you a reason to keep moving forward in your world travel until the ending.
The story isn't memorable, but it's not obnoxious. It's fine. The cast is entertaining enough to make it a pleasant journey.