Well yes, Dungeon Siege is not exactly known for it's hardcore RPG elements <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />
Using only one weapon has a downside. I would suspect it's easier to kill a skeleton with a club than with an arrow as such there could be monsters where a certain weapon is not so effective. You would need one hell of a bonus on the weapon then to do some harm.
Although there certainly are merits to be able to train your skills instead of buying skillpoints, it also puts a higher strain on balancing I think. In a party system you can balance this out by selecting characters who are skillfull in different types of weapons.
