you gotta make your maps bigger without making more empty spaces. this is smaller than a koth or even some arena maps. players will get tired of playing the same area over and over. theres also no places to really defend (chokes, areas with lots of cover and short sightlines) except a sentry spot on the final control point, but mostly there should be some kind of progression into separated areas for a 3CP.
use some props, pillars, hills, or displacements around control points to make them more fun to attack. if me and the enemy team see each other at a far distance everytime no matter what route we take, there is not much point in having alternative routes nor will there be "anywhere worth going" which could just be some cover or a height to take hold of.