In its technical form if you put all the skill points into all the weapons to unlock them and then points into the Weapon Mastery attack then yeah. However, you wouldn't be able to equip One-handed, per se, and and be able to use a WM attack that is not under the One-handed weapon tree. Example: if One-handed has WM for Two-handed (melee) and Hand blaster (ranged) thats all you would get access to. You wouldn't be able to use another weapon's WM like staff that has a different WM Two-handed or Hand blaster attack. (I know those aren't accurate but I wanted to paint the picture alittle for you)
You can spec into all weapons and their combos and be able to use any weapon, but would cost around 130 skill points, other than that Charles is right and you're limited to whatever weapon you're using
....that one day we'll be able to buy skill points. I know it's highly unlikely, but it is reasonable right? For those who want to progress further and play higher level raids and such, and get keep getting sh** on by high SP people who say they don't want to waste their time with us in their group. I'm fine either way, I'll still play when I can, but it would be convenient I guess. I don't get to play much with my job, but I love..and have spent a lot on this game.
