Conclusion

Developing a platform to support a diverse set of requirements such as Battle.net is certainly no easy task. Though the original design could have perhaps been improved upon, it is the author's opinion that given what they had to work with, Blizzard did a reasonable job of ensuring that the service they set out to create stood the test of time, especially considering that support for all the future features of their later game clients could not have been predicted at the time the system was originally created. Nevertheless, it is the author's opinion that a system designed where clients are untrusted and all actions performed by them are subject to full validation would have been far more secure from the start, without any of the various problems Blizzard has encountered over the years.