Marking bugs as "helpwanted" is fine and does capture the essence of the desire from a committer standpoint. However I believe this is not enough to engage with the community. Why? Because the codebase is huge and without knowledge of where to start, there is almost no chance for someone to succesfully help.
So what? If you, committer, really want help, you should give a few entry points in the code where to start investigating the problem and if you, community member, really want to help you should ask for those entry points.
In PDE/Build we have done that for a few things that we did not had cycle to fix and the feedback has been great. So why don't you try and see if it helps.