Good stuff! It kind of makes sense that Casual games are amongst the lowest rated. There's nothing wrong with casual games, but it'd be a bit paradoxical if millions of people were like "I mean... I just kind of play these games when I'm bored or just want something simple and kind of fun to do, BUT ALSO I DEMAND THAT ALL GAMES BE CASUAL GAMES, AND I WILL PLAY THEM LIKE HARDCORE WOW-RAIDERS!" Haha. I think everyone "likes" casual games, in that, if you're stuck in an airport terminal, you'd probably rather someone hand you a phone with Candy Crush on it or play Fallout Shelter than do nothing (obviously you could read a book or something, but I'm just talking about options with your free time that involve playing games.) But it's not really going to dominate the gaming market or anything.
Also, though, you said "we know we can't please everybody," and while that's true, it's also less true than you might think. The DLC aspects are a good example. There's probably an inherent reason why people tend to favor the big, deep DLCs and expansions. While some people might really like small DLCs, too, the biggest reason for people to dislike the larger ones is simply wait time. So, if you make people wait, you're making them unhappy, but it's still VERY likely that you're going to inevitably make them super happy when the expansion, etc., actually releases. Hardly anyone's going to say "I loved this big, full game so much that I REALLY wish this big, full expansion had just been a bunch of really tiny things, specifically." Especially when it's optional. So, as with most things, while you might have group A favoring thing X, and group B favoring thing Y, chances are, if you do it right, and both groups appreciate the general goal you're going for (they're not purist racing game fans complaining about your medieval fantasy RPG, for example), then you ARE going to please everyone. Some people just end up more pleased.
The biggest factors are the functional ones. There's "I feel this UI is clunky and think it could've been a different way that I prefer," and then there's "this task is actually difficult and bothersome to do in this UI design, and even the people who like this UI layout agree that this part of it could've been designed better." The subjective bit's going to get a lot more easily overlooked (and people are still going to enjoy the game, quite probably), than the objective part.
So just keep that in mind, and keep at it! You guys have such a great attitude about game design! Thanks for doing so!