Definitely (b). Right now, I do spend "copious amounts of time monitoring" the Stack Exchange metas. But I will not be able continue to scale beyond many more sites.
That's why I am in the process of appointing and organizing provisional moderators until the Stack Exchange sites can hold their own elections. Besides the normal Moderator activities, part of their function will be to act as ambassadors — liaisons between Stack Overflow and the individual sites — to identify and bring these issues to us.
If there's an idea/feature-request for a specific community, it's up to that community to vet the idea in the same way we do here (i.e. in their own meta). If the idea passes muster, it would be passed on to us for consideration, through their own governance.
Of course, if the idea involves the core engine or the Network, the idea should be raised in http://meta.stackoverflow.com. Pretty cool, huh?