Many low-level foes got a boost. For example, the hobgoblin warrior still does an average of 12 damage when an ally is adjacent, but now it has advantage on that attack. May not seem like much, but against low-level opponents a couple of them are now a much more dangerous threat. And if they are alone, they still do the 12 damage if they hit. The bugbear, gnoll, goblin, and kobold warriors all got more hit points than their 2014 counterparts; not a lot, but enough to give them a bit more staying power against the upgraded 2024 PCs.