Well, there are a lot of possible responses to this: I mean, the basic and most fundamental one is the 'clue hammer' response. If I'm fundamentally interested in what the narrative does, and in a clear explication of the story, then I don't GENERALLY want a lot of small factors contributing to each activity, as it is not really a very clear and concise 'story'. So, I tend to shy away from the more traditional 'stacks of situational modifiers' approach.
That being said, when you have something that is, let us say, 'environmental', it could be manifested as a single permanent modifier that is included in the situation. This might be a way to implement something like "I inspired everyone with a song" for example. However, there are a TON of other ways for that to be implemented as well, so its not like anyone needs to die on the hill of 'there must be stacks of modifiers'.
For instance, in HoML we have power, measured in power points. Power also has a source, which can matter when you get into doing stuff outside your normal 'shtick'. A 'bardic inspiration' could thus give you a power point, or allow you to use power as if it had a different source, both of which could be significant. It could give you a permanent bonus to your DR, produce some sort of action economy advantage, or lots of other things. Honestly, once you stop focusing on stacking bonuses, a lot of other options could open up. Heck, maybe there should be an 'inspired' condition, that would be cool!