Trojan Pony wrote: I like the bench to be mostly for extra SP's and platoon players.
You're overthinking. The bench is for owners to make the adjustments they think they need to make to win, and it is up to each owner to carry the bench he thinks he will need, based on his roster.
I like a deep(ish) bench -- something like 3:1 active:reserve. This allows for adjustments to nagging injuries, rainouts, and pitching matchups without having to deal too much with FA. It also allows someone to add a weekend start or two if needed without 'streaming,' or to platoon.
Making more active slots along with the bigger bench does not change much. More active slots = more need for adjustments.
Be excellent to each other.