(I'll assign this to myself for now actually, I don't think anyone from Mojo core needs to work on this directly)

There is a decent use case for wildcards and I think we should be mindful
of it.

Consider building something like a UI shell with a launcher that wants to
tell any service "please launch with some default UI". That was the
original intent behind the "app" capability (which of course was grossly
overused and abused).

Maybe we could allow wildcard requirements iff an additional service
manager capability is explicitly required by the service?

In any case we can definitely get rid of 99% of all wildcard uses today.

Will need to give more consideration to wildcards, how they're used, and whether or not there's a better way to support such cases.