Just theoretical as I probably won't play Shadowlands.
I am levelling a frost mage and I enjoy the feeling I am 'frost'. Personally I don't like the idea of getting fireball since I like this feeling of specialisation. I DO think classes can be a tad more complex, just because a) they are too simple (though not that simple as people seem to think) and b) it gets boring having the same spells all the time, I miss getting new spells in expansions. That said, I like the idea of shattering throw for warriors (I used to play/play a warrior a lot), it doesn't 'feel' like it should be a spec specific ability and it's cool and adds depth, complexity and possible counterplay (PvP perspective).
I don't like the whole covenant system as usual there has to be some grindy new feature to boost playtime, it's artifical complexity just like azerite traits.
I think each spec getting maybe 2 or 3 new talents, as well as maybe ONE or TWO spells made classwide will be fun, but I don't want spec homogenization, I like spec identity.