Some dirt, scratches etc. on the canopy glass seems reasonable. However, as all objects are in focus in DCS (i.e. no depth of field), canopy imperfections become far more of a hindrance than they would be in the real world. When I get a scratch on my windscreen, I barely notice it as my eyes are focused on objects beyond the scratch. For this reason it would be nice if the canopy dirt, scratches etc. were toned down a little -- especially when checking six etc. and you're trying to look through all of them accumulated along the line of sight through the glass.