I believe particular new training courses would be good, especially USAR, Technical Rescue, Fire Ranks, etc.
If Police have the ability to have Sergeant and Inspector Education Courses, Fire should be able to have Crew Manager, Watch Manager, etc.
Some of the other courses you have stated are good as well and would help myself too. Perhaps with some vehicles being added too to facilitate these courses would be good, like, Criminal Investigation Department, Forensic Services, etc.
USAR is definitely a possibility to look at bringing in the future especially with the PM and Rescue Pods being pretty much un required. The same could be said for tech rescue but may be further down the line.
As for Station Managers/Officers, Group Managers and Area Managers in my opinion these are represented by the "Fire Officer" already. Which is essentially the same as "Police Sergeant". If future developments allow and it fits these roles may be revisited.
With Crew/Watch Managers this would add to the realism and could possibly be introduced to the game after some tests and thoughts into how/what would work within the mechanics.
Thank you for your suggestions