I actually really liked the message in Clerks II. It was about two middle aged guys who were just coasting at life because they felt ashamed about how running a convenience store actually made them happy. Ultimately, a simple life is all somebody needs to be happy sometimes, and fuck anyone who judges that.
It's a simple, yet effective message that I thought was pretty refreshing for a movie. Most movies for normies tend to be about "You can be anything you want if you just reach for the stars!" Clerks II was about being happy with what you have. I felt like Kevin Smith was actually trying to say something with this movie, and I think he did a good job at it.
For Clerks III ... Jesus. I don't know how they can continue the story. The second movie ended on a pretty perfect note, and I feel like making another one betrays the pretty strong ending that Clerks II had.