Problems I see:
Testnet needs more work to make it mirror production behaviour.
Voting need to become more robust and visable with more information at hand to users.
The UI needs an update to simplify it in some areas and also deplay more relevant information.
The NN needs to be ported to C++ (currently underway)
Builds and verison control needs to be made more robust, The codebase and GitHub repo is a mess. Lots of obsolete and conflicting information.
Gridcoin needs cleaning up and a proper build system putting in.
(I think they are planning to use auto tools or something, Its half implemented as far as I know)

The way Devs are paid isn't the most ideal way, given Devs submit their own times which can be falsified, I'd prefur fixed bounty amounts on specific coding tasks. Like port the NN to C++ £1200 in GRC bounty. Seems reasonable, then we can vote on the bounty amounts.

What I'd put as priority 1 (after getting network stable again) would be getting the development cycle, testing and building streamlined and automated as much as is reasonably possible.