I don't know if anyone has posted something like this before (I apologize if they have) but my idea is simply to have clear blocks that you could see through.
Pro's:
1. Can be used for windows, in vehicles and buildings
2. More realism, you can see into buildings
3. Provides cover, and also line of sight
Con's
1. May be hard to create (I'm not a programmer!)
2. It takes three shots to take down a piece of glass? This is not realistic, but it's a game... oh well.
3. Could be misused (Entire walls made from clear blocks. It's stupid, but would probably be done.)
Please give me more feedback! Thanks!