One of my biggest problems is how cramped the maps are. We have a power player who picked barbarian who has 15 ft reach thanks to giant posture and he cheeses every encounters with AOO (he took fighter dedication) trip and grapple. At this point as a GM I feel I have 3 choices in this matter...
1- Change the enemies in a way that counters it (like giving spell casters hideous laughter, give rouges the non provoking feat and give a lot of grease)
2- Reintroduce the 1st ED rule where he can't attack 5 and 10 feet with a reach weapon. Which will either force him to a standard melee weapon or reposition himself.
3- Ask him to preroll as he is cheesing the map designs..
As a GM I'm conflicted because I want him to have fun in the game but I personally not enjoying any encounter due to him cheesing. Also he complains that I'm crippling his cheese build if I introduce anything that specifically counters him. What should I do here?