The Client Failover Service suffers from the same issues as AVEVA Adapters before the AVEVA Adapter Configuration Utility was released: you need to constantly check against the documentation and make sure that you spelled parameters and their values correctly, that your numbers are in range, and that you typed commands correctly. If you are using configuration files, you need to check your syntax for things like improper escaping of special characters, missed commas or quotation marks, commas after the last "}", accidentally using ")" instead of "}", and other cortisol accelerants.
Also, configuring the Client Failover Service is part of configuring an AVEVA Adapter, even if it is optional, so giving the Client Failover Service a GUI allows you to configure every aspect of an AVEVA Adapter purely from GUIs.
Lastly, since the Client Failover Service does not have nearly as many actions or parameters as AVEVA Adapters, allowing it to be configured with the AVEVA Adapter Configuration Utility would add negligibly to the space needed by the AVEVA Adapter Configuration Utility.
However, if it is decided that the Client Failover Service should not be configurable through the AVEVA Adapter Configuration Utility, then it should at least be given its own separate optional GUI program, similar to what the AVEVA Adapter Configuration Utility is for AVEVA Adapters. It does not even necessarily need to be web-based.