The idea of lazy-initialization of SOAPProxy has been discussed ad-nauseum in the forum thread: SOAPProxy initialization and deployment ordering. I know it's a long thread, but it's worth reading I believe.
The biggest problem I believe is when I said, "If we went with a lazy approach, then we would have a deployed service for which we would not be able to expose WSDL for! We need to pull in the WSDL on initialization so we can transform it and provide it to consumers of the ESB. If we went the lazy way, we would get more bug reports from people saying 'WSDL contract unavailable!'".