A few more things after a few more months of play...
*You regain HP a lot quicker than you used to (all HP after a long rest rather than 1 HP). This makes extended dungeon crawling much more practical than it used to be.
*You can have a lot more variety in party construction--you don't necessarily need a full cleric, and there's a bunch of not-wizards (sorcerer, warlock).
*Characters get extra abilities at given level points. In 1st ed this was more or less just the monk. The fighter also gets a bunch of extra attacks the other fighter-types like barbarian and paladin don't, which makes sense as they are the specialist in that area.
*If you use milestones for advancement, there is less incentive to kill everything you see.