One of the things I like the most about 5E is that "only" around 30% of the PHB (28% actually, by my calculations) is spells. Obviously that's still a HUGE chunk but in 3.5 (and yeah, now that I think about it, any PHB I've ever really looked through) LITERALLY HALF (at least) of the PHB was spells. Collapsing "sleep, sleep harder, and sleep hardest" into one spell called sleep that scales with level was a great move (collapsing vertical spell trees). Collapsing horizontal spell trees (changing six second level spells named after animals into one second level spell called enhance ability) in addition really gave us the most reasonably sized spell section I think we're ever gonna get.
While I'm singing its praises anyway, 5E feats are implemented so much better than 3.5 feats, which especially after all of the splats came out were just crawling with way too many underwhelming choices and outright trap options (and I don't just mean the ones everyone knows about like toughness) while you would find the occasional diamond while dumpster diving (while there were many, many broken character builds you could make by combining feats that were never meant to be combined, the most obvious 'feat to rule them all' from the core of that edition is probably Improved Initiative, of which the 5E version of is pretty damn good too). Grammar is hard.