I had a lot of trouble identifying with Kaim as well, though by the end, I can say I enjoyed the story. As with any good JRPG the sidequests (pipot, backyard and the crazy amount of customization in learned skills for the immortals) kept me hooked.
Having played Enchanted Arm, Blue Dragon, Eternal Sonata and currently Tales, I'd say LO was my favorite by a fair amount, though that is IMO only. Also, I am not very far in Tales so reserve the right to change my mind.
To your questions though, I do think that many of the bosses and to certain extent some of the more powerful enemies need a sound strategy to beat. If you beat the final boss in the backyard though, expect the end game boss to be a cake walk...I don't remember the name of the boss at the backyard, but he had some pretty devastating moves.
