Hi Michael,
The Vault team generally determines the need for a service pack based upon larger technical considerations such as updating the database schema or providing technically complex solutions. We are sensitive though to the proliferation of hot fixes and do look to roll these up where it makes sense and release product updates intermittently. There are of course production dependencies and a larger effort that goes into producing an update which means it is not always an efficient use of development time.
Having said this - 24 seems to be getting to the upper end of a reasonable number hotfixes and I believe we will look to provide an update in the near future while 2011 is still supported.
Hope this helps.
Allan
Product Manager
Autodesk, Inc.
