Several proposals for ways that configurations will change in Horde 4.
In order to reduce the amount of up-front configuration needed, I propose that we either:
Configuration data needs to be encapsulated instead of being thrown around in the global scope. Having a general Horde_Config class, with the defaults in that class, would allow for easy implementation of option #1 above.
In many cases config options should be controllable as policies, either on a per-user or some other larger but not site-wide basis. This should also integrate with vhosting support (i.e., a config policy per vhost). See HordePolicy and perhaps HordeSpaces as well.
All options, whether this is MIME helpers, preferences, configuration settings, etc., should be settable from the configuration GUI.