It's cause it's two games stapled together. The first half is a short 'Tales of' game, with some ridiculous anime bullshit setpieces (in the best way), the second half is a monster hunter clone, and probably the best monster hunter clone ever made.
I can sorta understand why the devs would add that for the people who just jived with the monster hunter combat portion of the game and weren't down with watching some of these really long story cutscenes about the power of friendship or whatnot.