Opportunity Attacks

Status quo

Opportunity attacks are meant as a control feature for martial characters, so nobody just runs past them and then targets the backline.

The problem(s)

While opportunity attacks do (kinda) solve this issue (spoiler: they don't), new problems arise from this:

• Once you are in melee range, there is no incentive to move, because you don't want to give your opponent an essentially free attack. Sure, there are situations where you want to trigger an opportunity attack to burn the reaction of your opponent. But this only covers about 10% of cases. Most of the time the only reaction creatures have is the opportunity attack. So you don't have to make a decision what to do with your reaction; you just need to accept a gift.
• You cannot run. Sticking to hard rules, if you want to flee from combat, you have two options: either disengage and hope the opponent does not run after you. Or dash and take one hit but cover more distance. The first option feels really bad, because you spend your action running. And your opponent can just use their movement to catch up and then still attack with their action. The second option is also trash, because your opponent can just dash as well and then we are back in melee range. In both cases nothing about the situation changes, except that you got attacked. So you will eventually go down.
• Both previous points lead to what most combat looks like: on turn 1 go into melee range and then attack without moving for the rest of combat. Which means we can just forgo battle maps completely. You can fix this by creating other objectives on the map. But you don't want to do this for all encounters.
• And worst of all: opportunity attacks actually do very little to stop a willing creature to target your backline. They just run past you and take one attack - most creatures can easily take one hit. And a little damage never stopped anyone. And here comes the fun part: once the creature is within melee range the opportunity attacks work against the backline. Because as stated above they cannot run away. But since they probably suck in melee combat they are effectively useless now. And now the opponent can just take them down super fast, because they cannot defend themselves and neither can their melees.

Goals

From these problems we can infer a few goals that we want to work towards:

• Less static combat
• Usage of battle map features
• Actual control for melees
• Create more decisions
• Possibilities to run away/reposition/regroup

New Rules

• You can now disengage using movement speed instead of an action, usally 10 ft (value up to debate, if we need more complicated stuff, we can do 5 ft $ \cdot \lfloor \sqrt{\text{CR or Level}} \rfloor$) per enemy you want to disengage from. Now you can actually run away and maneuver. You can still use the regular disengage action to disengage from all enemies at once.
• If you are wielding a melee weapon, your attack range is difficult terrain for enemies. So it is harder to maneuver in close proximity or run past the melee. This gives more control to melee fighters.
• If an enemy moves to within 5ft + your melee attack range, you can use your reaction to move 5ft towards that enemy and halve their movement speed. This is to prevent running around a melee's control area.