I hate the standardisation of spell lists. I really like Warlocks and part of that is their unique spells. Hex and Armor of Agathys and such. Yes there are some subclasses that get some of them, and ways to get some of them with feats, but they remain rare outside of Warlocks. Now Bards can hex.
I don't like Clerics getting all the Paladin Smite spells, I don't like Paladins getting Spirit Guardians.
I don't like bards missing classic Bard spells.
I like that paladins and Rangers having unique spells and think their should be more of them (although most of the Ranger ones are not very good but that is another issue).
Standardising the list makes for less interesting classes rather than more fun and different experiences from each class.
But I do like that Ranger's became a prepared class rather than spells known. I don't understand why rangers were designed this way in the first place when Paladins are prepared casters. Rangers are not as powerful as Paladins and shouldn't be more limited in their spell choices. Many of the spells on the Druid/Ranger list are useful but rather situational, being focused on being in nature. It would help to be able to change them when you are in a city or dungeon or travelling in natural surroundings. Having played a Ranger recently I found it difficult to choose useful spells from their list. There are some obvious choices but after those it is not a great list. Being able to change things up would make it better although it needs more help than just that.
I think it is okay for Bards being changed from known to prepared although I don't think it is required, I don't really care either way for Bards, but they do need their own unique list.
I don't think it is good to make all classes the same in regards to preparing spells. I like there being differences in how you deal with spells. A difference between playing a Cleric vs a Sorcerer vs a Wizard.
Having an optional rule in the DMG for making all classes into Prepared Clasters would be a good idea. But don't homogenise all the class. It doesn't make everything interesting and more fun.