What'd that look like, that's different from what they do now? Trying to imagine what developer input to that would look like. I think a lot of devs already feel like existing PM tools they use for sprint tracking and such are worse than if they pushed more planning into git or somewhere otherwise closer to the code, so getting buy-in might not be so hard if devs got to be a little less heavy in a bunch of not-actually-that-useful-to-them tools on a day to day basis.
I think 1/4 of the challenge is what tool to use and 3/4 is convincing and motivating people to be reliable and forthcoming with accurate information. A good project manager demonstrates he or she can add value, unblock things, escalate and communicate appropriately, and not just be the Project Police.
I’d love it if developers would be willing to collaborate using a dedicated project management tool and leave the bug tracker for bugs, but the chances of that happening voluntarily are nil. You gotta go where everyone else already is.