right off the bat calling your own suggestion "OP" isnt very convincing since you're basicaly admiting that your idea is not balanced against the existing mechanics/weapons.

secondly, the suggestion doesn't work with the mechanics of supermechs. the base concept is you get hundreds of items which are divided into subcategories (Torsos, side weapons, Top weapons, Drones etc.) and each has a given function. so it is therefore not true to the concept to have two items "attatched" to eachother like that. it also removes a lot of the freedom from the person who will get these two weilded together items to create the mech how ever they want with the parts available which is the essence of super mech's appeal, total freedom (within the weight constrictions) to design your mech how ever you want.

then to adress your second suggestion of the "deadly Assassin" I dont really see the need for it to change between sword and gun when you can already make guns that fire at range 1 such as the demolisher series. the mechanics would also be too complex and not realistic enough to fit with the game imo.
you've also provided no stats for it so I dont really know at all what you have in mind.

and as a side note: stop saying pls so much its (Want to be allies? Sometimes I like to pretend I am a princess riding a pony..) annoying to read.