Currently if a cap ship is maxed out with invited gunners, no one else (except the pilot can dock). This sounds like a bug to me because invited gunners should not take up much space.

Well. It isn't a bug. It's an implementation choice.

So, I guess if you want to make a Suggestion about handling the player counts on capships differently, I'm open to that? But it should be on Suggestions, and would probably need to be a bit more well-defined of a proposal.