Current international 752 (and soon to be A321XLR) routes have very little competition, so UA won't be compelled to install a more competitive product in business. Only routes I can think of that competition have better J seats are EWR-ARN (SK A330), ORD-DUB (EI A330), IAD-MAD (IB A330), all of them are seasonal routes for UA. TP also operates EWR-OPO/IAD-LIS on A321neo but debatable if those J seats are better than B/E diamond.

It would be interesting to see what seat UA picks for the 28J 737MAX10, and if that new seat will also be installed on the A321XLR.