Opportunity attacks have their long way in the world of tabletop games and D&D in particular. 3.5e/PF both had an exhaustive list of actions which can or can not trigger an OA.

5th edition simplified things a lot. [One single trigger left][1]:

> You can make an opportunity attack when a hostile creature that you can see moves out of your reach.

It seems the developers consider this particular trigger as the most important one. So what happens if we remove it?

The reason I ask is because there are 5e-based games which does not have OAs at all (Five Torches Deep, for instance), so I want to know, how a typical 5e gameplay change if the DM introduces "no opportunity attacks" house rule.


  [1]: https://rpg.stackexchange.com/questions/44402/