I'm not sure if it is just me or not, but I find that tanks move very very quietly, I've seen instances where I'll be at the corner of the building and without warning a t34 rolls past making as much noise as a tricycle. Sound is a very important part of being "situationally aware" and not being able to hear a tank 10 feet away is quite dangerous to ones health.
If this isn't just my problem and is a game thing, then this game isn't as realistic as I had hoped. When a tank is pretty close and moving around it should be quite loud and therefore a bit scarey. I just can't get worked up about a couple tanks assaulting a little town I'm hiding in when I can't even hear them. Maybe if I heard them coming I'd freak out a bit sort of like what real infantry might have done.