c) roughly neutral - no major issues foreseen
There are two rogues in my current campaign, one has "Assassinate", one has "Fast Hands". Assassinate rarely comes up, but when it does, it's powerful. Fast Hands, on the other hand, comes up all the time, but it's not a big deal. The rogue mostly uses the ability to swap weapons freely, or more rarely, uses the extra interaction to pull a lever, or open and close a door on the same turn, or something similar. It's convenient, but not powerful. So swapping the two abilities should be fine.