Comparing the MDR of Princess with P&O - Definitely P&O is aiming at a younger, more contemporary look. The MDR on Princess is the same as it always was - several large oval tables that can seat 10 and several 6-top tables with a limited number of 2-top tables. White starched tablecloths are used. The MDR on the Pacific Encounter has all square or rectangular tables, most are for two people only. They don't use tablecloths even in the evening. The tables are dark slate grey, but I feel the decor has avoided the look of a factory cafeteria. I don't mind it.
On Princess we asked to share tables and were not at the same table every night. On P&O, we stayed as the same table with the same waitstaff every night. We didn't ask for this, but were very happy as our waiters were great. At the time (end of August into Sept) P&O didn't sit people at shared tables unless they were travelling together. Princess was operating the way they always have. If you want to share, they seat you at a larger table, but the option not to share is available.