Yes, I would love some help. I will even share some of the donation revenue with significant submissions that are incorporated into the code base.

See this thread for a long list of feature requests. Feel free to pick one of interest.

You mentioned comments and tagging, and those are good candidates. Both of them seem simple on the surface but need to be thought through and will end up being quite a bit of work. Comments, for example, need the ability to be enabled/disabled, moderated, and occasionally deleted by an admin. Tagging needs to have a super easy workflow so that large numbers can be easily and quickly tagged, coupled with a good way of viewing all items that match particular tags.

My plan was that before I started these - especially the tagging feature - was to study how other apps did it. Pick the best ideas, throw in some innovation to be the best, and then get to work.

How you want to contribute is up to you, but if you hope to have your ideas incorporated into the codebase, you should keep the lines of communication open to be sure your architecture fits with the current system and my ideas for moving forward. I can help design the architecture and spec out some of the detailed requirements if you want.