Some weapons should already be upgraded!

I just started my third playthrough, so obviously I love the game, but I did think of one improvement that would make the game significantly better... Imagine if the later weapons you pick up were already somewhat leveled up. They did this with Rogier’s Rapier and it was so cool.  

After a play through, you realize that 99% of the loot you acquire is basically worthless. You can pickup endgame shields, weapons and spells in Limgrave. Basically when you progress later in the game, if it’s not a smithing stone, or a Rune, then you’re not using it. 

It would encourage you to try different weapons, as you don’t need to waste all your smithing stone resources just to see if it’s any good. This way, you are experiencing more of the game. Devs put so much work into the variety of different weapons, yet most people use 3 or 4 weapons for their entire play through. Imagine picking up a weapon that is actually an upgrade of the one you’re currently wielding!  You would actually get a buzz from collecting a +7 spear, and it could help you on your journey.

I understand that being able to sprint to Calid and pick up a +18 weapon would have balancing issues, but at least loot from bosses should already be appropriately leveled up in my opinion. Beating Godrick and getting his axe should be an upgrade on the sword you already have, even if that sword has greater late game level-up potential. You should feel that the twin blades you get from beating Radahn will be of use to you in your journey. It should feel like a "reward", not a trinket collectable.

As you prgress through the game, the smithing stones you get become more valuable, as do the level up runes, but the gear doesn't. Shields you collect during the endgame aren't as good as the brass shield you get from your first enemy encounters. At least if those endgame shields were already leveled up, you would have incentive to use them, until you can level up your brass shield fully.

Are there any issues with this that I can't see?