Yup NBB has its own way to grow. But why I suggested this feature as core is because as we all know, NBB is undergoing heavy changes with each updates, right? So chances of plugins breaking are a lot. So if all features like SMTP, embedly which are required the most, are to be outsourced from plugins, a forum admin might go confused, when he updates nbb from, say 0.7 to 0.8 version and majority of plugins go berserk. I was first thinking to suggest that the main NBB team can themselves maintain a couple of plugins which are regularly updated with corresponding core nbb releases. But then, you guys are already busy with nbb, I can see how often you tweak NBB in github, which shows all of you are giving it your best.
So I thought it would be better to adopt the most necessary as core. Once NBB becomes stable, then all these incompatibility issues will subside a lot, also by then more active developers will start releasing and updating their plugins. Hope you take this on a positive note. @julian