1. Improve threads
2. Improve C API support
3. Give local::lib, cpanm by default ... multiple perl versions by default
4. Give direct support for coroutines / async await
5. Mark experimental features as non-experimental (attributes, signatures)
6. Pick an OO system, package system
7. Make switch cool again
8. Get more core modules or remove some. Give more visibility to cool perl modules. like PDL or something.
9. Improve GUI toolkit, Web Deployment and Web Assembly support
10. Improve look and feel of community sites
Heck break some backwards compatibility with Perl4, get rid of format.