Last Resort has always been a meme but at least throwing axes have given the talent a weapon that can make good use out of it. Unfortunately throwing axes themselves are a bit of a meme so…
As long as the current trigger condition remains, it will never see use on any weapon other than throwing axes. Here’s an alternative possibility that somewhat retains the core idea. Have the trigger instead be an empty mag, then it’d be usable with any of his weapons, and you’d have an interesting dynamic where you’d have to weigh up when it’s better to have your weapon loaded and ready to go, and when you want to leave your weapon unloaded to get extra oomph in melee.
2 problems I see with that idea though. Firstly 25% power might be a bit much for that trigger condition, since getting a reload off in a pinch when you need to with RV isn’t too difficult.
Secondly the talent currently affects the last bullet fired, and if that interaction persisted with the new magazine based trigger it would be way too good with handgun and crossbow especially; however removing that interaction would ironically make the skill much worse with throwing axes, which would be pretty sad.
Anyway that’s my 2 cents, might honestly be better to replace the talent with something else entirely. The work required to make it decent without changing the idea too much may well not be worth it.