You could add some cover in the middle of the cp. This cover can act as a wall to prevent a direct sightline. Any direct sightline from the spawns is a bad thing. Even when during a test it doesnt go wrong eventualy it will when other players play it. Its fully depending on the sniper behaviour.
I however still think that your glass idea wasnt bad at all and i rather dont see you remove it at first unless you already tested the change i did. If people still think they can walk through just add some props near that window that indicate its a wall. For example some wooden boardings on the lower part of the glass, or some fence. Still, i think glass does enough.
