Crumbling infrastructure needs the most attention, and I include aging (and most likely leaking) city water & sewer pipes in this category. Public parks and green spaces are another critical issue in many areas.
@janbb also mentioned libraries, but I wonder. Are they the essential community resources that they once were? With the internet available as an information source, and with the rapid expansion of ebook availability (as well as electronic subscriptions) I see public libraries as slowly fading in both importance and popularity.
I base this assessment on my own experience. I acquired my first adult library card in 1967, and continuously maintained a library card until a few years ago, when I let it lapse. Despite being an avid—and frequent—library user for most of my life, I have not set foot inside my local public library since last September, and I don’t miss it at all.