I'm surprised that two classes I really like-monk and warlock-attract such hate. Of the monk: 5E has finally done it right. BTW, the eastern flavour is not compulsory. Of the warlock: I'm still playing my 3.5 warlock and she's just gone epic level. I like what 5E have done with them.
I also like 5E barbarians, druids, fighters and paladins.
The classes I dislike (rationally or not) are cleric and wizard. I've always hated having to choose which spells I prepare every morning (from a list which grows with every product released with no theoretical upper limit). The martial/caster disparity starts right here.
I voted for wizard, and would never play one if I had a reasonable alternative, like bard, sorcerer or warlock. Thus, I haven't played a wizard since 2E.
Actually, I gave the last 2E wizard I played with such a low Int that the 'max. spells known' equalled the 'spells/day', just so I didn't have to pick and choose every morning. And she was a fighter/mage, so there!