Adam -
There is some internal disagreement on the extent to which deleting the user who created a GeoEvent Service, Input, and/or Output connector will have on a service's viability. One consideration is the type of input(s) and output(s) participating in the service and how exactly the service was designed. If you'd post a screenshot of your service with a description that would help as we work to collect empirical evidence to support/refute some assumptions.
/RJ