I don't know if this has already been suggested, but so far in my SWTOR experience I haven't seen weapons that level with you like the Valiant Jedi Armour set and other adaptive armours.
So what I am suggesting is for the same to be done with weapons; for example, you can purchase a blaster pistol at level 1, and have it at all the way to end game with the 'attack' stats increasing as you play, and using modifications to keep improving other stats, the same for other weapons (eg. lightsabers, vibroblades, staves, double-bladed lightsabers, rifles, cannons, scatter-guns etc.) just like what you would do with adaptive armor.
What do you guys think?