The last Spenser books by Parker fell apart and Atkin's were more of a formulaic attempt to duplicate Parker. They were
1. Full of quips
2. We all love Susan, the greatest therapist and most beautiful 85 year old out there. Since Spenser fought in Korea, that's the age bracket.
3. Hawk, the cliched sidekick and Spenser - the greatest H2H folks ever.
4. Never heard of any new guns
5. Old time gangsters who shot as well as John Wick but would rally to Spenser in time of need.
The Jesse Stone follow ups were a touch better. Perhaps the genre needs a Crisis of Infinite Earths to reset all the series.