One major area of improvement is Memorial Glade. Back in the late-'80s / early-'90s, that whole area was littered with the so-called "T buildings," the temporary barracks-looking structures that had been there since, what, the 1940s? For an urban campus, I think UC Berkeley's planners have done a pretty good job of maintaining open spaces.
Faculty Glade remains timeless, Memorial Glade is open and sizable, the eucalyptus forest and the big crescent lawn above Oxford are all open areas, and there's some tranquil paths around Haviland Hall. It's a delicate balance because the central campus is only about 180 acres total, and the student body has grown by almost 40% over the past 30+ years.