To me the map is of great quality, but the problem here is that it is quite a lot for the Cube engine to handle. A map of this detail would be better off in some higher-end game (e.g. QuakeIII, Urban Terror, etc).
The reason why you can't put flags is probably because you've hit the entity limit of the map.
Also, based on what I can see, the textures you're using must be huge in comparison to the usual, am I right? That's often going to be a problem for older computers. That's why many of the standard maps tries to make do with small repeating textures (except for ac_douze).
As a rule of the thumb, the best level of detail of AC maps should be slightly above QuakeII.
The reason why you can't put flags is probably because you've hit the entity limit of the map.
Also, based on what I can see, the textures you're using must be huge in comparison to the usual, am I right? That's often going to be a problem for older computers. That's why many of the standard maps tries to make do with small repeating textures (except for ac_douze).
As a rule of the thumb, the best level of detail of AC maps should be slightly above QuakeII.