is it too much dirt and scratches ?
you might try using a baked AO texture to make the dirt texture focused more in the groves and corners.
the texture itself looks great!
It depends… it could be a choise of style? if you do a quick search for column on the web you will have reference images. It depends very much on the environment and so on. If it is a game prop then I would personally prefere a more suttle texture and leave the contrast for the things that need more readablility.
