You can always come up with a seemingly rational argument for keeping any player but the counter-argument is always going to be "we don't need what they bring right now and by the time we will need it, this player will no longer be able to bring it."
Get rid of everyone at or near 30 years old and any late 20-something player with trade value. I want a near complete turnover of this roster. The sooner that happens, the sooner the rebuild can end. But the heavy lifting of a rebuild is the getting rid of players and then waiting for the players and picks you get in return to become something. Step One is getting rid of guys. Every vet you hang on to delays the rebuild. They are progress-stoppers. Impediments. Nothing more.