In my modest experience seats 45AC and JL are the best Economy seats on A350. The lavatories are at some distance behind, the proximity to the galley means prompt service by FA and, last but not least, these are the only duo seats. Moreover, there is plenty of storage space (after takeoff) between the window and the A/L seat. Even on Seatguru there were comments challenging the negative opinion of these seats. The only problem is if one has short connecting time - these are the last seats on the plane and, thus, the last to disembark.