This I very much agree with. I don’t mind the overabundance of other genres, but I feel like more often than not they have a serious tone/mature themes. I always appreciate it when there’s humor or silliness involved, although… when it becomes the focus of the story I tend not to enjoy it as much.
I generally don’t want to read dark and sad stories. There’s always the news for that. 
It’s not really a “genre”, but if you look at the list of tags there isn’t really much in all ages fiction. I mean, I get that it doesn’t have as much of an audience, but I’m young at heart so I feel disappointed that it seems to be overlooked. People seem to be more interested in “more mature” stuff (not that I dislike it necessarily). 
I mean, just look at my WIP.
Anyway, I agree with the slice of lifey stuff too. There’s a certain appeal to it–everyone wants to do awesome fantasy things, but there are other things you want to do or experience in real life too (or a story in a realistic/modern setting).
Even other genres can use a few more slower paced scenes.
What do you mean by meta exactly? Well, in my WIP the characters will eventually discover the fourth wall and the plot will revolve around it. 