There are issues from two different directions here.
- Keeping an opponent from getting away from you.
- Keeping an opponent from getting close to you.
Both are difficult to achieve in turn-based combat, particularly without feats (ie: Sentinel).
The only job that has built-in movement control is the Cavalier Fighter, and that's not til level 10. (Hold The Line allows AoO against a target that moves
within the fighter's threat range (rather than just when leaving the threat range), and reduces the target's speed to 0 if hit.)
The lack of 'live' movement significantly hinders certain types of cinematic fighting, such as a swashbuckling style, or the big fencing scene in The Princess Bride. You can't move as part of the reaction to the attack, which means the fight stays in one place with people metaphorically hitting each other in the face. That in turn means that difficult terrain is actually less useful, because it can't interfere with an ongoing fight; it can only affect your ability to get to a new target.
The Scout Rogue has a feature that kinda approaches this, with Skirmisher allowing you to move half your speed as a reaction after an enemy ends its turn. This does help provide a lead for escape, if that's the rogue's intent, but it doesn't help during the fight itself.
In terms of keeping someone from getting away, I'd consider that a successful AoO should reduce the target's speed by half. If the target has already moved half its speed, it can't move any further. Sentinel and Hold The Line would still be better, directly reducing speed to 0, but it would at least provide a
little bit of control against someone trying to get away from you.
In terms of keeping someone from getting close, I'd consider allowing the use of your reaction to step back one square for every square the enemy approaches, up to the limit of your move speed. Any movement used on this reaction is deducted from your next turn's movement. The attacker will want to maneuver you into a corner to pin you down, and getting hit by an AoO when trying to escape that point would reduce your speed, allowing the attacker to more easily catch up.
And for in-combat movement, I'd consider a "Fallback" ability, usable by anyone trained in martial weapons. In this case, each time an attacker makes an attack, you can fall back 5 feet. The attacker can step forward 5 feet to make his next attack, of course. Both combatants would need to consider the risks of AoO's from other people on the battlefield that they're passing through, as well as difficult terrain. Being hit by an AoO when using Fallback should negate the movement, as well as any further Fallback steps.
Note: This is an issue that has bugged me for a while, and I've written up several variant rule ideas. The above are just my current thoughts.