I'm not sure how Littlefinger could find Gendry and even if he did I'm not sure how useful he'd be. By this point most of the people that knew Robert well enough to confirm his bastard are dead. Sweet Robin is basically a promise that the Vale won't be enemies but not much else. Not like Olenna has someone to marry him to now that Marg is the queen and definitely been bedded.
That said, shorter seasons sound great to me. The books are already guaranteed to have more material than the show and the fewer episodes, the fewer chances there are to spoil things.