I had a similar thread and question back in the day.
I'm inclined to agree with Taran on principle, but disagree on the numbers -- in my game, we treated the shield as Weapon and Armor:2. I'd say it depends on the size of the shield. A buckler I'd put as 1, a bigger, circular shield like the vikings had at 2, and a full-sized riot/Roman shield at 3. Using it as a weapon doesn't need a stunt at all.
As for stunts, a +1 to attacks with the shield isn't bad, but I feel like that would make using the shield as a weapon almost too attractive -- why bother swinging the sword when your shield can do nearly as much damage and you have a +1 to hit? I've tended to favor the approach of boosting maneuvers or blocks done with a shield instead. Because while a shield can be a weapon, that's generally not its primary purpose.
For the taking a hit, yeah, that can be handled through aspects. Interestingly, I've had characters with such an aspect both invoke to take a hit and receive fate points for taking a hit in different circumstances.
Another thing to create the same effect is to roll blocks with your shield -- with the above Stunt, you could roll with the shield to create a block against enemies attacking your pals, as they have to get through you first.