How's that any different than the system we have now? A fully masterworked gun vs a 1 masterwork gun you pick up? At least in the system I've laid out you'd be able to upgrade that gun by simply using it, which is how you'd figure out if you liked it anyway. You'd also be able to use cores like the system we have now to upgrade if you so choose. My system wouldn't change things for people who like it the way it is now, it would allow them to continue to use cores to upgrade, similar to D1 system using motes of light to upgrade instead of using the weapon itself to do so. I'd also love to see a "shooting range" somewhere at the Tower where you could test your weapons on targets and maybe even moving targets, but that's another discussion.