Preprint of Portal Angel of Mercy with original flavor text.

Angel of Mercy fills a number of holes and I'm happy to add it. I need a 5-cost creature that can finish a game by its lonesome. The set could use more flying, and while life gain in white common isn't necessary, the angel lets me check it off my bucket list. It even makes sense flavor-wise... the flavor text of Homelands infers Serra and Feroz left Ulgrotha, never to return. These Angels of Mercy are the few creations of Serra that decided to stay behind and help protect the plane in its time of need.

The only other oddity is that the Angel is common. But... well, it is. the only reason it's been hanging out at uncommon for 15 years is because of its creature type.

There aren't many common 3/3 fliers these days, for what it's worth. They're normally 6 mana rather than 5, and usually blue. It won't break anything, but it'll be one of the Limited defining commons. I think that's pretty much what you were going for, though :)