I'm fine with classes in role-playing games, but in fiction it puts me off. Not fatally. The author can still win me over, but it puts me in a "oh, one of those" frame of mind. It's a bit like an author having a character who is a lawyer and expects the reader simply to buy into the stereotype with no actual character development. Or politician or dockworker or what-have-you. Assassin irks me because nobody ever had a job like that. There were the Assassins during the Middle Ages, and they were something very specific (pace Assassin's Creed). There have always been plenty of political assassinations, but that doesn't imply the killers did nothing but that for a living.
Since I'm venting, thieves guilds bother me as well. I'm okay so long as I don't think about it. At all. Once in a while an author can manage that, but it's rare. It's not how guilds work, for one thing, and it's not how thieves work. Thieves form gangs, not guilds, and that's really what gets under my skin. A guild is not necessary. Not for a plot, not for worldbuilding. It is (far too often) merely a conscious or unconscious call back to D&D with the expectation the reader will form the same mental image as does the author.
All that said, I fully enjoyed the Dragonlance books back in the day. So there you go.
Since I'm venting, thieves guilds bother me as well. I'm okay so long as I don't think about it. At all. Once in a while an author can manage that, but it's rare. It's not how guilds work, for one thing, and it's not how thieves work. Thieves form gangs, not guilds, and that's really what gets under my skin. A guild is not necessary. Not for a plot, not for worldbuilding. It is (far too often) merely a conscious or unconscious call back to D&D with the expectation the reader will form the same mental image as does the author.
All that said, I fully enjoyed the Dragonlance books back in the day. So there you go.