Title says it; basically suggesting you add the ability to upgrade low-tier weapons to higher tiers via infusion, so like for an example let's say you get a tier 1 of something that has a great park combo. Currently it feels kind of useless to hold on to if you can't upgrade it later, so my suggestion would be if you get a (for example) tier 4 or 5 of that same weapon, you can infuse it to the tier 1 to bring it up to that higher tier. This would maintain the weapon grind and add value to lower tier gear... Feels like an easy win.