I've played with the idea of roster size before, including:
Unlimited team rosters. Monday, August 3, 2009
Dress 25. Saturday, September 1, 2012
Increase the active roster but only dress 25. Sunday, September 9, 2012
Recently we've had this nonsense:
A-Rod replaced by a pitcher. Wednesday, May 4, 2016
Alex Rodriguez has been placed on the 15 day disabled list. Initially his spot on the roster is being filled by a pitcher. Maybe this is for only a day or two but it does not bode well. The Yankees have 8 wins and 16 losses.
Yankees Constantly Tailoring Fringe of Roster
By BILLY WITZMAY 16, 2016 The New York Times
Read The Times article for yourself. It has details on what a rocket scientist Yankee GM Brian Cashman is, without naming him. The roster manipulation by Cashman actually makes sense and might occasionally provide an advantage. However, a small advantage doesn't help much when the organization overall is weak.
The point of this post is to point out that the simplest thing is to keep this simple. Just increase the roster of active players. Unlimited was my initial suggestion but 30 works pretty well. It's got to be demoralizing and discouraging for players to be called up to the big club, only to receive little, if any, meaningful playing time before being demoted again.
Those five extra roster spots merely acknowledge the reality of big league baseball for several decades: starting pitchers will not be used on days when they do not start. While their identities rotate from game to game, each team has at least four starting pitchers who will not play.
Make the entire active roster active.