One of the controllers in Lihue in the USA told me on my last visit that controllers would not be prepared to change the Class E above their tower to Class C, and also control it without radar and without additional staff, because the strain and workload would be too great.
Of course, Lihue is a contract tower operated by Airservices under contract with the FAA. I don't know how it works with the contract guys, but FAA controllers aren't really in a position to say that they "would not be prepared to change" airspace class based upon anything.
Dave