If this new fork can bring new life to the project, modernize the codebase, introduce new features, fix long-standing bugs, and allow contributions to move forward more quickly, then I think it could be a very positive development.
Transmission has been a great project for many years, and seeing renewed development and fresh energy around it can only be a good thing for its users.
I'm looking forward to seeing how Retransmission evolves. Good luck with the project!