Hi Tuckernut,
1) You can already do that. Go to Office -> Income Statement. Then select your base in the top right corner in the drop down menu.
2) General marketing campaigns affect the global company image as a whole. Doing a "general campaign" that is not
general makes no sense really. What you probably mean is a base-specific route image campaign (promote
all flights from a specific base for a given time)? If you mean that, I think it's a good idea since doing route campaigns for every single route is a really time-consuming. Other marketing options (conventions etc.) are basically just a play of words since the only thing that matters is money spent. If you spend it for radio ads or conventions, doesn't make any difference in the end.

3) I think it's just fine as it is personally.
What I really would like to see, though, is the option "Minimum lease time" when leasing out airplanes. We already have "Maximum lease time", so why not "Minimum lease time"? No more people that lease for 6 months, change the seat config and just annoy other people...