One of the fighter talents I’d love to see in play (I have a Battlerager Vigor fighter in one party I’m GMing for) is the Brawler Style. Weird though it is, a brawling fighter would be like a close-quarters controller — technically, by being defenders, they already serve precisely this role — giving the fighter the opportunity to nail his targets to the floor.
I recommend going with Agile Superiority to make sure you have a high Reflex to prevent “acrobatic” foes from escaping your grab attacks — it also allows you to chase them down and knock them down if they throw all their actions into trying to escape. Using a combination of grabbing and knock-down powers (like the at-wills Grappling Strike and Knockdown Assault) combined with feats like Pin Down and Vicious Advantage, the fighter can use his powers to prevent an enemy from ever getting up or even posing a threat.
The best I saved for last, of course: World Serpent’s Grasp, a feat from Heroes of the Forgotten Kingdoms, allows you to knock prone an immobilized enemy when you hit them with an attack. Combined with feats I mentioned above, use Grappling Strike to grab a foe, and on the next turn, before the grab ends, you hit it again with Grappling Strike (plus combat advantage granted by Vicious Advantage) and knock it down with World’s Serpent Grasp. Using Pin Down, your target is now on the ground and grabbed by you until the end of your next turn (or it tries to escape), and unable to stand.
Give your game master the gift of stun-locks. *cue evil laughter*