I didn't email appstorepromotions, but I'm p known to Apple at this point through previous games, and it's definitely a good idea to email them. I read about that in the thread for The Contender as well, and it has served Faisal well from what I see!
That said, the reason I keep coming back to "Make A Good Game" is that I know games that were featured by Apple and still didn't do very well, which is a shame. I'm a bit weary of the whole "what's the trick" discussion because even if there were a secret shortcut to guaranteed features (which there isn't), you could still end up getting nothing out of it.
As far as what a good game is, it's subjective but there are things to keep in mind. Good art, easy to understand interface (i.e. your gameplay can be complex but people have to be able to understand what's going on and what buttons etc to press immediately), compelling enough gameplay / enough content / replayability to keep players coming back, and integrating as many platform-specific features (Game Center, Google Play Services, ReplayKit, etc etc). Good screenshots / video on the store page and a good icon also matters a lot.
EDIT: Kappsule is owned by GeorgeN, who handles Android ports for some Stencyl devs.