I have been thinking about this since reading the proposal and have been putting off my reply. I am going to try to keep this short to no more than a few short paragraphs as no one wants to read a long winded rant. I want to start out by saying I 100% think breaking weapons should always be a thing in PSU, loot is PSU's end all be all. Hunting drops and doing TA is the only thing to do when you reach endgame in a game like this. That being said I am not against finding a way to make all A+(x) and S+(x) useful while still making grinding a risk. Without weapons breaking and losing potential they have no need to be replaced outside of weapon percentage on striking weapons.
Weapons not breaking when we know they will be replaced by something better in a few weeks time makes sense as they will lose most if not all their worth, and the fun factor of finding something better comes into play with new drops. However, unless the developers are going to endlessly add new content and new gear until the day clementine shuts down the server at some in the game we wont see new items. All there will be left to do is search out the perfect items, build the perfect palettes for whatever type(s) you play.
Having a system where weapons break keeps the hunt alive, yes some people are going to have better RNG, some people are going to be able to play the market and afford everything they ever wanted and many of us, myself included will never have the top percentage of the best of the best gear. However, that doesn't mean you wont have good gear, the game is still playable without that perfect set. Not having that perfect set gives you something to log in and strive for. Having an imperfect palette challenges you to change your playstyle from someone else and to think, "what's the best weapon and PA to use in my arsenal for this situation".
The only people who it truly hurts to not have the best of the best gear is Time Attackers as some of their competition may have an advantage over them due to having gear that is marginally or even significantly better than theirs, which I am very understanding can do a lot when it comes to clear times, but we shouldn't balance the game around making everyone equal. Weapons need to break, it keeps the market alive and the hunt endless, breaking weapons is a good thing you get something else to look forward too. I accept that if numbers that have been told to me are correct 95% of the things I bring to grind will not be 10/10 and that is okay, without full custom power the difference in damage on most weapons is marginal. However a 5% chance at 10/10 is low and I understand why that would upset a lot of people, that is why I am not against making grinding odds a tad more forgiving, however stuff needs to break and breaks need to be more common than uncommon in my personal opinion.
/end long rant that I said would be short.....