I just booked my first trip for 2017 in business class (D) on United (UA 962 EWR-TXL) and it shows the 2-1-2 configuration for rows 1-6 on 764. Recognizing its more speculation than science at this point, any advice on whether the middle seat is more desirable than any others?

Interestingly enough, the return flight (UA 929 LHR-ORD) is also designated as Polaris business (D) in my reservation notes but the physical configuration is the traditional 3-classes of service.