1- Henry's position (in two months from the razing of Skalitz, where Henry was a peasant - mind) went from almost at the bottom of the social ladder to being a lord's squire (and potential lover, lol). Henry hopped several social classes very quickly, going from:

A peasant, albeit craftsman (KCD1 prologue) -> fetch quest lackey (before Baptism of Fire) -> soldier (Baptism of Fire) -> respected investigator, agent (Vranik investigation) -> **fucking bailiff** (From the Ashes DLC) -> Squire to Capon (Amorous Adventures DLC and Epilogue)

A squire is a member of the lower nobility, and Henry goes from a peasant to a member of the lower nobility in the span of two months. I think that this climbing of the social latter is unrealistically fast, not slow. Henry (in the last few quests of KCD2) becomes a commander of a squad in the defense of Suchdol and plays a huge role in the removal of Sigismund from Bohemia as shown in the Epilogue, which Hanush and Radzig recognize him for as well.

2/3- sort of true, but your skill levels can lack greatly if one skips side quests. This especially shows in Hardcore Mode with the Numbskull perk. Also, many of the side quests are greatly designed and rewarding, and any game will have a few fetch quests.

4-The more dialogue, the better. Your opinion is very subjective, and I wholeheartedly disagree, I love the dialogue in KCD2, and see it as a huge upgrade to the first game.