I have travelled a number of times on Ryanair recently. On one occasion it was from Stansted to Toulouse and back, uncharacteristically the aircraft was sold less than 100 each way. I boarded last as I could not be bothered queuing, amusingly all the middle seats were taken and all the window and aisle seats were empty thus clearly demonstrating that the algorithm has changed and that not many people were prepared to pay for a seat. As soon as the crew called “boarding complete” everyone jumped up and re seated themselves with their travelling companions again, the crew made no attempt to stop this. The return flight was the same.
All my other recent trips have been as a single traveller on full flights I have found that checking in late on the App has always given me a window or aisle seat, I presume that all the middle seats have been allocated by this point.
I don’t see any change to the Ryanair policy unless the extra revenue from the sales of seats is offset by the loss of on board food and beverage sales caused by the stag and hen parties being separated all over the aircraft and thus not drinking them dry. Personally I suspect that most people will know that they are likely to be split up and will buy seats to ensure that they are not and in the end Ryanair will win.