I'm not happy about current situation...
- MS does offer a content life cycle feature for o365 groups where SharePoint sites also included at the end , but classic sites no solution available, now on top the possibility creating modern sites without an o365 group, also this site type excluded from the retention configuration
- you can configure on tenant level a second site admin mandatory but not used for all site templates, self service modern team site and communication template different handling, one example
- you can configure site sharing settings on tenant level (which level is allowed to set), classic sites are after creation in status disabled, modern sites sharing enabled if you not modify the default template and a trigger
- if you connect later a o365 group to a modern team, site, template not changed,
- no clear identifier for scripts and automations for which app a o365 group is used (Teams Planner, site only, Yammer, PowerBI, etc)
- same with naming convention concept o365 group names, some apps, services you can configure, other not
- the script based auditing, also be able to trigger automations based on the output, more and more complex, several tools with limitations in parallel required to make an inventory, main reason get-spo, pnponline, get-unified group, get-teams have all different output and restrictions, for example using get-teams as Azure runbook, all the time looping with 3-4 modules