Yeah. There are a quite few niggles like that. Even though you can get quite close by (automatically) sending code to the repl, Python is simply not set up for interactive development.
It's one of the main reasons why I love Common Lisp so much.
Still, it's not too bad and IMO a lot better then restarting the process on every single change
I've not used emacs for python, but could give it a spin for this!
Bit unfortunate that you need to restart the process for re-evaluating classes though.