This is mostly a personal take but I feel like the current weapons don't have an insane amount of variety. The 3 weapons just feel like different flavours of kind of the same weapon. Especially the Sword and Shield and Dagger. The parry mechanic on the dagger and the block/perfect block mechanic of the Sword and Shield aren't identical, but they're functionally serving the same purpose.
I propose a rework for the dagger to make it stand more as its own thing, trying to play more into the "rogue" fantasy. I think it'd be cool if I could go invisible for like 1.5 seconds and get my next attack enhanced coming out of the invis, or a "shunpo" where I teleport behind the target and do a backstab of sorts.
If not a full-on rework of the weapons to diversify them, then a system where I can equip a skill onto the weapon. Some players might want to stick with the parry on the dagger, but some players might swap off the parry to use a smoke grenade instead. Maybe on the Greatsword, instead of the spin move, we can get a Guts flip where you somersault through the air and slam the blade down on an enemy. I'd love if Sword and Shield got some sort of "bunker down" move where we stand completely still but block attacks from all directions, like a power guard... You know, really become an unbreakable wall.
Anyway, it's just a fun suggestion to give the weapons a bit more spice and identity. Please consider it <3