[Sean D]

or you could go for option C: make an application that will take as input the source code that makes up different features and combine them to form the final source file that will be compiled, outputting the plugin. obviously, it wouldn't be very flexible: the features would probably have to be almost entirely independent from each other, but it would give users the ability to pick and choose exactly what they wanted from a large (feature-rich) plugin, such as UAIO.

but in terms of a single vs multiple plugins, you can't really go with one over the other all the time, because it really is dependent on the type of plugin and the usefulness of each particular feature. in your example, you would want to keep that all in a single plugin if each "feature" was small enough, because each one would be fun to try every now and again on a server, even if you used only one or two of them most of the time. in some other plugins, though, where features are large and independent, it may benefit the author and users more to keep its modular parts in their own plugins.

what it all comes down to is how often each feature gets used by each server, and how inconvenient it is to use them whenever desired. or maybe it isn't inconvenient for server owners at all to switch plugins in and out using config files; perhaps you're asking the wrong question entirely.