For my money, I really enjoy Bacco and think we haven't seen enough of her. She has, after all, only appeared in eight books (A Time for War, A Time for Peace; Articles of the Federation; Destiny I: Gods of Night; Destiny II: Mere Mortals; Destiny III: Lost Souls; TNG: Losing the Peace; A Singular Destiny; and Typhon Pact: Zero Sum Game). Realistically, given the sorts of events TrekLit often depicts, the Federation President ought to appear far more often.
She also appears in Typhon Pact: Rough Beasts of Empire, so nine books.
Just for the record, There are no scenes with Bacco in Gods of Night. So subtract that number by one.