"tried some of her others weapons but none seemed usefull for pvp."
Then you haven't tried her FOCUS KAA7, 'cus that thing just shreds in pvp. Hell, i'd be pretty surprised if they don't nerf it soon. Amazing crit, fast reload, no need to wait for it to target etc.
She's still very viable in covering other Raiders or just holding down positions as an Antag. Try it, it might just change your perception of Shae.