Damn, I was thinking of posting that concept... Oh well.
Yes, it's a very good idea. Slow-ing is almost always the kind of status condition a defender wants to hand out, as it makes the "I'll willingly take that one hit if it means I get away from this guy" approach unworkable.
Warden is a great MC for a Fighter because it allows you to take Perception as your free skill, and it opens up all of the Primal feats that are not class-specific. There are even a few cool Paragon Paths that work without any hitches, if you want to add some interesting flavor: Storm Sentinel, Child of the North Wind and First Hunter.
I'm also intrigued by the idea of a Dragonborn Knight with Iron Vanguard and Draconic Arrogance using the Hammer Hands stance. Any work been done on that concept yet?