Having read the raw I can say it was a very nice end to a very fun series. Not the best, and I can understand some people's dislike, but still pretty darn good.
As far as those that claim there's no development, I'd say they're half right. Nishikata does get a lot of development. Through her he expands his horizons, starts up new goals, and gradually becomes a better man for his time with her in comparison to the wimp he was at the start. The one downside is that, while I do love her character, Takagi didn't honestly have all that much going on. I don't recall any significant development, and frankly she seems like she might be a bit of a "satellite" character, as most if not all of her character that I can remember is centered around Nishikata and getting him to notice her. The author was still able to make it very entertaining which is a testament to his skill, but I might have liked it if Takagi had more that she did on her own for herself, goals that she was pursuing just for her. Could still be inspired by him, just like his ambitions and efforts started with his attempts to cope with her teasing, but give us a bit more. In comparison, Nagatoro has both main characters grow and evolve, pursuing their own individual dreams often inspired by the other. This series is able to get me for its "moments", those instances that are just so sweet or romantic, but I'll recognize they could've put a bit more into the characters themselves.