Whats is the general level of difficulty in this game?

Its difficulty is fairly balanced, overall. Combat starts out relatively challenging, but overleveling, decent equipment, and good Force/item strategies in combat can reduce the difficulty quite a bit. The difficulty spikes again in the last third or so of the story, and the final dungeon is plenty challenging, but nothing that can't be overcome with some preparation.

Compared to other RPGs on the Wii, it's easier than Baroque and Fire Emblem, but harder than Chocobo's Dungeon and Super Paper Mario.