They will not get removed since it's a feature as explained by Aaron. Yes, some weapon are more powerful, but that's why they are not free, unlike regular weapons from /wep cmd. About Shrewsbury shotgun, players can also get them from crate island or pick dropped weapon. You can also buy other custom weapon from ammunation or pick them from drone's crate.
Anyway, the range of following weapons were reduced: Custom Shotgun, Spaz, Stuby and Shrewsbury shotgun..