I tried using it for some serious work a while ago (a good while ago - not that I suspect it has changed much in the interim). I think the basic problem here is that it's just not a native app compared to the rest of the suite.
I'm pretty sure that some significant portion of it was written in Java originally, and that the original idea was something along the lines of teaming up the form side of Writer with some convenient local database and XForms support or something. It was always tremendously buggy, though.
I would be surprised if LibreOffice managed to do anything with it; if I were them, I would scrap it and start it again as a native app that fits in with the rest of the suite. This is probably a time-consuming route though (which is probably why Sun never attempted it).
Getting Access compatibility would also be hellishly hard at this point. Modern Access has a cut-down version of SQL Server inside, along with lots of other high-powered gizmos - it's actually a very powerful system - and that's before you get to all the scripting goodies.