Course I would. Smalling wouldn't have played as well as Fellaini did today for starters. Aguero would probably have at least 2 goals in the bag if Smalling was marking him.
The point is, no player should be play acting. It should be a red card offense. Its embarrassing to watch and football is really becoming a pansy sport. That "headbutt" (and I use that term loosely) was nowhere near strong enough to bring a man down. The refs should be stricter with their decisions. If someone does what Fellaini did, it should be a warning NOT a red card. They need to start giving the benefit of the doubt and if it was infect malicious, use the video technology to implement a ban AFTER the game is played. Simple as that.