I recently spoke with someone in a league with rosters under 25 offensive players, no IDP. In a league like this, the rookie draft only needs to be three rounds. His draft was five. There simply is not enough room to hold the drafted players at that point. It diminishes the pick value and the ability to let players mature. It takes away one of the key dynamics in dynasty which is being early on a player.
I told him to use everything in the third, fourth and fifth to move up. Package it all or package some with players. Anything past three has a good chance of being on the waiver wire in six months. If you play in shallow rosters, start seriously looking at your roster and thinking of who to package. If you have multuple later picks, put them with one of those players and try for a first or second. Players with immediate or second year impact become much mlre important.
Shallow rosters changes a key strategy from holding players to consolidation of players/picks. Some players can still be held, but to win the upside needs to be better than that of a late pick.