We need to quit making excuses for him. He might not be playing with all the 1st string offense- but he's not playing against all the 1st team defense either. It's a mixed bag. If you are not seeing improvement now, then it's time to find someone else. Ian Book will never be an NFL starter. The best he will be is a backup.
Ian Book is not going make this active roster. The questions - is he worth stashing on the practice for a "just in case" need or can the Saints find another project QB to put on the practice squad.
Book may make the Practice Squad - but next offseason or at the draft, it's time to find another QB. Dalton could likely be the backup for a few more years. He's only 34 now.
The 3rd QB needs to be someone with a high ceiling... instead finding someone with a high floor.