It's my partner's favourite part of Tokyo - all those vintage clothing/bag shops are just perfect for her. I've been visiting for almost 30 years and I think the exposure has altered the area detrimentally and I agree that the station "upgrade" won't do any favours.

When I'm asked (which is often) where the best places are in Tokyo I always point Shimo-Kitazawa out and then recommend Koenji as an alternative as I prefer the latter; quieter, smaller and cooler.