These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Designated Hero: David, increasingly towards the end of the book, is a mere looker-on at the dramatic resolution of others' subplots, including Micawber's expose of Heep and (less plausibly) Dan Peggotty's rescue of Emily.
Fair for Its Day: Among other instances, a lot of readers think Dickens' shipping of the Peggottys to Australia after Emily's fall from grace is unfair, but the book actually was a fair look at prostitution at the time (and that kind of thing really happened, too).
Not to mention the local prostitute, Martha, is treated as a sympathetic figure. Her Only Friend Emily clearly cares for her, helps her to go to London and start her life all over again, and later she helps Daniel and David to find Emily again.
Foe Yay: Uriah gets very touchy-feely with David, who for his part, is fascinated by Uriah's strange appearance. Once he compares those reddish brown eyes to "two glowing suns", and another time, when Uriah has wormed himself into David's home, David gives in to an irresistible temptation to watch him sleep.
Jerk Ass Woobie: For some, Rosa Dartle is a massive bitch... but as a very tragic one as well.
Purity Sue: Agnes Wickfield, David's 'dearest sister'. Albeit somewhat more realistic than most examples, and even quite likeable in spots, she's clearly intended as the 'angel in the house' archetype beloved of most authors of the period. Kinda hard to ignore when she's introduced standing in the light of a stained-glass window, 'pointing upward'.
Tear Jerker: So many! Like Mr. Mell being fired and humiliated, David being told that both his mother and half-brother died, Barkis's death and the upcoming revelation that Steerforth betrayed David and Ham via seducing Emily, and Dora's death.
The 1935 adaptation, David, after finding his mother has married Murdstone and is booted from his old bedroom to a crappy, broken down guest room, tearfully reads a crocodile book, and then breaks down crying. It's hard not to feel for him.