What's something you want to see in a sitcom, but haven't seen yet?

You want people to come up with the idea for you? Typical.

I'm not giving you my ideas sorry.

Most sitcoms are terrible.  They're formulaic, repetitive, predictable, and often not that funny.  IMHO, the best ones are the ones that try to be a little bit MORE than just a sitcom by really doing good character work and having a story to tell OUTSIDE of the pure jokes.  

The Office and Parks & Recs became special because we came to care about the characters.  The Simpsons first 8 seasons as well as Married with Children (at first) were great because they were deconstructions and satire aimed AT other sitcoms.  South Park brought insightful political satire.  The Good Place actually tried to teach ethical philosophy in a 30 minute sitcom with an amazing premise.

So really write good characters that feel like real people we should care about and give them long term arcs that have them going someplace and telling a long term story.

I would also say that there are too few sitcoms that are genre parodies.  The sitcom shouldn't rely EXCLUSIVELY on genre parody (that's a recipe for being very short-lived as you will run out of gags), but pick a popular genre and lampoon it while you're establishing your characters and story.  The audience tunes in for the genre parody and gets hooked on the characters and story and more regular sitcom laughs that follow.