I'm a bit confused actually, which is why I think it would be nice to prevent this (as it would probably confuse newcomers too).
You seem to state that as soon as you'll finish your work on OSGi, we'll be required to have the Tycho plugin too. Then why exclude it?

BTW I'm not trying to hide the warning if there is a reason to need these plugins, what I'm suggesting is to write in the Eclipse section of the contributors Wiki what you expect us to do. I honestly have no idea what these plugins are and if Validator development is supposedly benefiting from having them or not.