I wasn't recommending using swift actions or some equivalent, I was simply pointing out those as examples of widespread effects from simple changes to the game's action economy.
In 4th Ed the reason for creatures like this is to make a monster by itself or just a couple monsters equivalent in danger to a large group without making them overwhelmingly powerful. So it really doesn't hurt the action economy at all if you make a bad guy like this. His extra actions are just to make up for the lack of other guys taking extra actions.
If one were just to give flat-out extra actions, I'd make sure to have limits on them so the bad guy can't just pile 2 or 3 actions onto one character. Going by the 4th Edition philosophy, which I think is good, the idea is to make them more of a challenge for a group. Have an extra action that is an area attack, or a scene maneuver, or a maneuver that can't be used to add a single target attack necessarily, or a free counterspell, or being able to turn a magical block into a free counter attack on someone...those sorts of things make a lot of sense. The idea someone had for aiding spray attacks is also good.