For short term priorities, I would list the Garage save load bug patch, and getting a new version of op2ext packaged. There's been a lot of good work on that project, though most of it won't be visible to end users. The changes are perhaps more valuable to maintainers, and maybe to some developers working on game modules. The main benefit seems to be that we'll be able to more easily write new patches. That is maybe something we should focus on for the next little while going forward, though not necessarily all for the next release.
I'm quite happy about the fixes for Plymouth Cold War. The crash bug had been long outstanding, so I'm glad that was finally diagnosed and fixed. New missions would always be good. I often feel we had a disappointing lack of new content, so it would be good to increase the variety of levels to choose from. The lack of new content is something we probably need to focus more on. I believe we need to reduce the barriers to creating new content.
I agree about patching the resource duplication bugs. Though that's going to hurt the speed runs that were posted a little while back. I guess they'll need to be redone.
I'd be fine if that got bumped to a future release though.
NetFix needs a bit of attention. I'm not sure how to estimate the level of work required, nor the time it would take.
I think we may need to put a bit of effort into more general areas not directly tied to a release. In particular, we could make some updates to the site to make it a bit more engaging. To get a bit meta, we may also want to produce more content about producing more content. There seems to be some curiosity about producing new content for the game, but because of the steep learning curve, many people get scared off after dabbling a little bit and then running into some sort of difficulty. Perhaps we could produce some walkthrough articles or videos that show how stuff is done. In particular, workflows for downloading projects from GitHub, or creating new levels from the template projects on there.
Related to that, we need a new map editor. The old one is unmaintainable. There is no legal free Visual Basic compiler for people who want to update the front-end. Even going the paid route, the Visual Basic compiler and IDE hasn't been updated in about 20 years. The back-end is written with legacy COM code, and old style C/C++ idioms with raw pointers. Most of the backend code has been rewritten into modern C++ style in the OP2Utility project, but there is no map editor front-end that uses it.