This is an interesting press release. In fact, what it does not say might be even more interesting than what it does say!
The first observation is that this press release does not say -- or even remotely suggest -- that Princess is eliminating formal nights. Indeed, the preservation of formal nights might be one really significant difference between what Princess is doing and what Norwegian Cruise Line (NCL) is doing! It's probably misguided to assume that Princess is attempting to copy NCL, especially when the press release speaks of differentiation.
The second observation is that this press release does not say how the line might accommodate such an arrangement on vessels that have only one main dining room, of which there are four -- MV Pacific Princess, MV Royal Princess, MV Regal Princess, and MV Crown Princess -- in the Princess fleet. Will those vessels be excluded, will they get another dining room, or is this press release the first hint of a plan to dispose of those vessels, either by sale or by transfer to a sister line?
A third observation is that the article does not say that the walk-in restaurants will serve the same menu as the dining room with fixed seatings. It appears likely that these restaurants may develop different themes at some time in the future if the concept succeeds.
The fourth observation is that Princess does appear to be progressing slowly on such a conversion. If it flops aboard MV Grand Princess, the company will have plenty of time to "change gears" before replicating the problems aboard another vessel.
The fifth observation is that this development is one that major competitors like Royal Caribbean International, Celebrity Cruises, and Carnival Cruises will have a tough time copying it because their vessels have only one main dining room (albeit multitier).