Ilbranteloth
Explorer
It'd probably have to revolve around SA. Range limit on applying SA. No SA with martial weapons? IDK. Getting pretty specific with /dagger/ (traditional D&D dagger, bladded stabbing weapon 12-15", shortsword, bladed stabbing weapon 18-24" - no, don't even ask about 16-17" bladed stabbing weapons, please, just don't... I'm sorry I brought it up, OK...)
Anyway, maybe d4 weapons can roll 2d4 on an SA? Or maybe the rogue can just roll 2d4 with a dagger on some even-more-easily-me condition than granting SA?
So-not-5e. ;(
DM must be always be involved.
I suppose we could get jiggy with stealth penalties. Carrying any item that's more than 2' long. Stealth penalty. Carrying anything with lots of little bits inside it (like a quiver of arrows) stealth penalty. 4' long items (rapiers were prettty lonnng) big stealth penalty. Spear/staff? Heavy Crossbow? Fuggeddaboudit (as they say in Thieves' Cant).
I'm not sure I follow. I'm not complaining that you can be stealthy when wielding a bow or a rapier. It's more about concept. A thrown knife in the back? Very sneak attacky (a la the old backstab). Also the idea of the assassins leaping out of a crowd with a dagger to slay the king.
But a bow or crossbow? I think that's a bit different. Aiming a weapon of that type is different, and takes longer to get a precise shot off. There's also a question of the range itself for me. Also, it's not something that you can easily conceal and then make that sudden, sneaky attack.
Which also lends an interesting opportunity - being able to make a Stealth check to conceal a weapon. I might limit that to light, one-handed weapons finesse (a light crossbow or sling would qualify, even though they need two hands to load). A successful Stealth check would work the same as hiding, the weapon is concealed, so you have advantage on the attack. This would not work in combat, probably first round only.