I'd put Blade leading a team of other monster characters, Werewolf by Night, Morbius, etc. and give the book a sort of urban fantasy/horror feel, like a Jim Butcher novel or the WOD setting. Call this the Midnight Sons and make it sort of the 'street level' book of the supernatural line. The deal with groups of vampires, mysterious cults and such, but don't regularly go toe to toe with guys like Dormammu or Nightmare.

Ghost Rider should have a solo about preferably Danny going arlound the country, and hunting demonic forces. I actually like the idea of the Spirit of Vengeance being an angel and a little bit out of control when it comes to punishing the guilty. I think it makes him a lot more terrifying then just being a demon.

Dr. Strange should have either a solo, or be the leader of a Defenders series with Hulk, Namor, sometimes the Surfer, and a few other faces. They are the ones that go out and deal with mystic threats on their home turf.

Punisher should just keep going around dealing with criminals and the occasional supercriminal.