I have 500+ lvls across my characters.. (more if you count the deleted 3 lvl 50s).

Traders are touted as "merchants" because their skills reflect an exchange. Just like a adventurer doesn't lvl from exploring. or a Martial Artist studying under a m,aster to advance in skill. Professions are named for their type of abilities. All characters are combat classes and need combat to advance. No one lvls from trade skills/adventurering/watching a higher MA fight or spar with them.

Traders are Ok at soloing... Without a crit buff though missions take forever. The only thing that saves a trader is the mez. MAs and all Pet classes are much much much better at soloing.

Shotgun is the only non blue skill for a trader. As pointed out there is nothing wrong with the working trader profession.

Shotgun range needs to be decreased... Nothing else. A shotgun should do massive critical damage but should have a slighter higher range than melee attack. A shotgun (ithica) shooting farther than a rifle is kinda funny.

Self buffed traders are no pvm or even pvp gods.
problem no one self buffs for pvp.

Finding a viable solution to outside buffs is the real problem.