The facial deformity, if that's what it is - a nod to the Pleasance portrayal of Blofeld? Maybe even a "reboot" explanation of how he got it - which those of us here who are trying to fit the Craig era into the overall timeline - I'm not! - will be flummoxed by. (Makes a nonsense of "Allow me to introduce myself" in the film YOLT, if that's the case.)
Another thing just dawned on me yesterday evening - the line from the teaser trailer - "It's been a long time, and finally, here we are". One way of looking at that may be that "Oberhauser" knew Bond years ago and they've finally met up again. Another, though, could be read as a kind of in-joke, because it's true - it's been a long time since Bond encountered Blofeld and "finally, here we are"
Usual caveat of course - assuming Christoph Waltz is playing, er, "you know who"!