Your claim "LO 4.0 is _no_ better than LO 3.6 at importing MS Office files" is simply false. Maybe it didn't fix the particular problems you're having, but there are incremental compatibility improvements in every new version, and the ZDNet piece mentioned several of them.
The fact that Word documents in which comments had been linked to ranges showed up in OO/LibO with the comment only at a single point had been a showstopper for a couple of my family members, who need to collaborate with others on editing and reviews. 4.0 fixes this, and though the fix won't make them switch over immediately, it will finally allow them, when the need arises, to do most of their work just fine on other computers besides the ones where they have MSO installed.
With reverse-engineered formats, it can be difficult to discover bugs. Please consider signing up for a LibO bugzilla account and submitting a bug report and, if possible, the problem documents. They've recently streamlined their bug submission process (https://www.libreoffice.org/get-help/bug/).