I think any better ways to make the site running smoothly will be a welcome idea, and adding proofs of reserved for exchange may be an added advantage.
In my opinion, more upgrades to the site is necessary to enhance users experience. The more the site improves in near future, the best for both new and the existing users. I hope to see team step up every areas that requires upgrades to boost further growth.
Please correct me if I am wrong, but the proof of reserves is mostly important for services that are financially inclined like casinos and exchanges, but for a service like Bitlist, making public proof of reserve may not be the ultimate lookout for development that we expect from this project, since there already have the mixer at the forefront of their service, and exchanges plus casinos come later, so having to verify proof of reserve is going to be a big headache and for that I advise that their focus more on technical development than channeling such energy to proof reserve funds since the service I multi functional having 3 financial services in one projects.
But all the same mate your suggestion is good, proof of reserve will only build trust for the project from its community, but have little to nothing in terms of service provisions which is very necessary, so advancing their services and making constant upgrades is for more preferred than posting proof of reserves.