When it comes to including plugin functionality themes, I’m on the fence. I like to keep themes simple and not have important functionality dependent on the functionality.

The problem with that approach, is that you often need to modify the theme to accomodate the plugin in a suitable manner. Many plugins add styling information to the site, and you really need that to be styled by the theme, not via the plugin, or else the plugin itself will require some sort of theming system which is likely to be a pain in the neck.

There are also features which are required by pretty much every single forum but are not available by default within bbPress.

And then there are features which are currently available as plugins, but IMO (and pretty much every other forum software out there) tend to include with the theme. Things like quick-quotes, forum stats and various bits of javascript spring to mind. I don't know of any bbPress themes which include this sort of stuff, despite it being the sort of thing typically included in a forum theme.

The other reasoning behind it is that people don't want to risk uploading 15+ plugins just to get their forum running. Every plugin is a risk, and at least with a theme, you only need to rely on that theme being maintained. However if a plugin developer stops working on their plugin you are screwed.

Having said all this, removing the functionality would be a piece of cake, it would juts be a matter of ripping out a bunch of folders and a single line of code in the theme. The functionality will sit on top of the theme as an added extra, it will still operate without it. Since the sort of people helping with the design side of things are likely to know nothing about PHP and vice versa, it shouldn't result in our volunteers being spread too thing across the project.

Here's the launch post for the functionality side of the project: