The second quality bar would be an absolutely terrible idea, both due to costumer expectations, and especially with the way grade VI materia works right now. Just like people will be expecting a crafter to HQ an item right now, they will be expecting a crafter to get a piece to at least have 4 guaranteed materia slots. Anything less will be considered a failure, due to the fact that an item with 3 guaranteed materia slots will have a lower amount of possible stats, since you can only overmeld one grade VI materia.