Personally, I run both paralysis and sleep weapons in group hunts so i can hold the monster down while my team lays down the damage, “Blast” if its Nergigante but never used Poison. I think the alternative elements are perfectly fine as is and it is more so that the players are not willing forgo their damage roles. That being said, if you were to make a monster only weak to the status effect elements, players are more likely to use element-less weapons like the Black Diablos bow or the new Tigrex weapons, so it does not make the other elements any more worth using than currently.