Another retired cop here...
I think the best option for a service pistol/revolver is choice. I'd like to have the choice to carry a reasonable service sized pistol, or a reasonable service sized revolver. Either would work in a police sized caliber.
The reason police departments dont allow revolvers these days is financial. They want only one training cycle, one training regimen. One caliber of ammo to buy in bulk, one training program.
My department allowed officers who owned revolvers to keep them as service weapons after the transition to auto's. The department also allows revolvers as off duty gun's. An officer can maintain qualification with either service pistol or service revolver or both. While no new service revolvers are accepted there is still selection of revolvers riding in their regulation holsters. S&W model 10, 65, 36, 640's, Ruger service six's in several configurations, SP 101's, Colt Metroploitan MkIII, Official Police, detective specials. As well as Glock 19's, S&W, and Sig DAO pistols. And maybe an occasional walther PP.
IMO training, and practice trump any particular gun. A department is better served by an officer who is carrying his choice of a firearm, with confidence , than one that he dont trust or like because it's cost effective.
I have carried a S&W model 10 or a Glock 19 as a service weapon during my career. I was happy with either.