The fact that #DMR #Radio IDs are already running out in some countries shows that the scheme is simply badly designed and outdated.
Just randomize them at this point, there's literally no point in keeping something around that only brings more headache and forces yearly checks, which will ultimately fail as the database grows.
And yeah, it might break some old stuff, but sometimes, you gotta break stuff to fix it, provided there is an ample enough warning before.
And to people that might say, "but it's easy to see which country someone is from using the ID alone": it's an ID. The database holds those records and the person is kinda supposed to tell you that during a contact, at least their callsign. Why would you rely on the ID when the callsign is there? We don't need everything to be indexed in some arbitrary case, especially when it matters so little as this.