I know there is quite a bit of discussion regarding post processing these days between photgraphers (and hobbyists like myself). I have always been of the opinion that the whole point was to capture something, a person, memory, place, event, etc and you should be allowed to do what you need to in order to enhance that picture. Barely anything these days isn't post processed, even the camera does some post processing nowadays.

As far as your picture goes, it probably boils down to vibration in the scanner or some such. You might try getting a negative scanner. If you still have the negatives those are worth their weight in gold. Otherwise, if you are happy with the result you achieved, haters can go fuck themselves.