I am a short story writer. I'm also something of an anomaly in that I exclusively write short fiction. No novels for me just yet. I'm having too much fun with the short stuff. But you know what I was thinking? IF (big if) I did attempt a novel, I would probably write it under a completely different pen name.
Two facts come to mind:
1) Novels sell better than short stories. They just do. They're more mainstream and, frankly, there are more people out there that want to curl up and be lost in a book for hours than there are people who want to savor and contemplate.
2) A large part of a short story writer's success is branding and expectations. People go IN to an Edgar Allen Poe story expecting it to be shorter.
It's impossible for a short story writer to completely avoid those scathing "too short" 1-star reviews. They happen. But the reason why they happen is because of reader expectations. The buyer wanted a long book, they got a short story. 1 star.
I see many authors sell a mix of short stories and novels. Even famous ones do this. But I'm not sure this is a smart business move. Put all the description and page count numbers you want, if your fans became a fan because of novels, there is a good chance they will be disappointed by a short story. People can't help it. They want more of the same. They don't want a sappy, romantic Clive Cussler. They want action-packed Clive Cussler.
When someone buys one of my novelettes and then a few days later buys the rest of the stories in the series, I know I don't have to worry about getting "too short" reviews. They've already read book 1 and they want more of the same. Therefore, if I put more novelettes out under that same name, people learn to associate that with this author they are getting this length of a reading experience. Reader expectations have been made.
Which is why I would probably start a new pen name for any future novels. I want a clean set of expectations.