that YF-23 is a really uncommon designed plane. nice!
It had to fit into the size of a F-15, so thet limits the heigth of the tails.
And the guys at nothrop know their stuff about stealth tech, which makes it into the flat tails.
Personally i think that the YF-23 should have been the definitive aircraft instead of the F-22. it has a smaller side profile, which will make it a more difficult target in dogfights.