Oh, I absolutely agree the car is surprisingly ordinary. But it sure looks striking. The Lexus ES and RX are easily their best sellers and they're closely related to the Camry. Many luxury buyers want quiet, comfortable and swanky looking. Some care about more. Lincoln seems to be going after the first group, but doing it badly. For one thing, they have way too many models. They don't need a mildly restyled Lincoln version of every mid-sized and larger Ford product. Cadillac doesn't do that. The ATS and CTS are only distantly related to other GM products. A little Corvette here and there, but mostly unique. The big XTS is made for traditional Cadillac barge buyers who don't care so much what's underneath. Even it looks decent.
If Ford doesn't think it pays to design a new platform for Lincoln, I think they can still offer some attractive models. The Fusion reputedly drives very well (CVT excepted). Ford can do like Toyota and build several Lincoln models related to that good model. Stretch it a little for a bigger car to replace the ugly Taurus-based model. Use the Focus as the basis for a new small Lincoln. Nothing wrong with its handling. The Escape and Explorer give you adequate compact and medium large crossovers. The giant Navigator is embarrassing and pulls in the wrong customers.
Anyhow, I haven't examined the details of the sunroof drainage on the MkZ. I've never had a problem with sunroofs leaking. The newer pop-up, slide back style may have a moat underneath, but the glass presses down hard on a rubber seal so there is little space for water to accumulate. Less than on older designs.