Pro 2. Neil Gaiman
The guy is a phenomenal author. He's written Sandman, one of the greatest comic series of all time. The fact he's contributing to Age of Ultron alone is awesome. If Neil Gaiman returns to the Marvel Universe, there is the possibility that he can write a LOT of great comics, not just for Angela, but for any superhero. He just specifically excels at great, mythic figures. Can Angela be Marvel's Sandman?
Con 2. Neil Gaiman
Despite being a huge fan of Neil Gaiman's work, I don't know for sure if it will mesh very well with what Marvel has in store. Gaiman works best when dealing with far-out, mythic concepts. Marvel has been grounding itself lately. Unless the whole Marvel Universe is heading toward a fantastic, mythic event arc in the future, will Neil Gaiman's writing style work? ...okay, yes, he will. Have you SEEN his stuff on Doctor Who? It's freaking awesome.
Pro 1. Nostalgia
Some of you might have picked up a Spawn book when you were growing up. As a child of the 90's, I grew up with a lot of the characters of that time. Spawn is one of them. As much as I liked the comics, Angela was probably my favorite of the characters. For a lot of fans of the character, we haven't had much of her lately. Spawn's universe is mostly forgotten by modern fans, and for good reason. The series jumped the shark a long time ago. Angela is a homeless character, being adopted by Marvel.
Con 1. Nostalgia is Blinding
Despite how much I want to see more stories for this character from my childhood, I have to remain slightly skeptical. The fanboy inside of me wants to love this idea, but there is just enough doubt in me that holds me from applauding out front. There's a reason Spawn died: it wasn't a very strong story. The characters were epic, but they weren't meant to last. The series should've ended after a 100 issues, right when Malebolgia was defeated. How much longevity is there in a character who occupied a universe that just wasn't meant to last? I don't know. The future is uncertain, and the jury is out. Whatever happens from here on out happens.