I think I end up with this subject every 5 years. We are an 11 domain shop. We have 6 domains that cover our 2 main and the original data centers. Others are all for the other regions, all which talk to the data centers. Therefore, we moved to using global objects across all the domains because it seriously cuts down on work and errors creating network objects. We do not use service objects as globals because the rule compiler does not handle shadowing well with a mix of global and local service objects.
So, "someone' has recommended that we curtail the use of global network objects (host, network, range). Considering it is create once, share versus, create numerous increasing the chance for error. Which is humorous in that I think the issue is the API application is including invalid characters. My guess from the limited conversation assumes that an invalid global is created, pushed, and then there are errors in each domain. Shoot, if they generated it wrong in the first place, they will do it wrong locally.
The philosophy has been maintain one object list, not many in X number of domains. It reduces errors, and now 80.30 221+ will show unused global objects.
I have yet to see a compelling argument that would make me change my mind.