Sure, why not? Overall it seems like BG3 homebrew buffs casters way more than martials. Giving rogues---and thus martials via multiclassing---a corresponding buff would help to even out that disparity.
It's barely any buff. Once the sneak attack is 2d6, the majority of damage comes from the sneak attack dice, not from the weapon. I played a rogue in a PnP game and I used a dagger. Another player asked me why I didn't use a better weapon. I said "1d4+3d6 versus 1d8+3d6 is not enough of a difference for me to care." Same here. 1d8+sneak attack (from a rapier) versus 1d12+sneak attack (from a great axe) is not enough of a difference for me to care. And if the house rule is limited to "sneak attack with any one-handed weapon," then there is no difference at all, because there is no one-handed weapon that does more than 1d8.
