I'm not sure if the motive is to enhance RPI/SOS, or because the members didn't want the 5th place team to miss out on the tournament.

I think the committee only looks at the top 10 (or 11 games) so pushing a game against a team with a low RPI out of that rated games and replacing that team with another game against a UNC or UVA so that is one reason.

I'd also guess that the coaches didn't like the idea that was done in the past were the 5th place team played a team like UPenn to prop up their RPI.

I also thought it was sort of weird to play their conference championship game a week before everyone else. Then they played another game after the conference tournament. I guess this doesn't change that too much just creates a bye weekend for the 3 teams no making the championship game. Not sure that is good idea either.

With the second weekend hosting only the championship game, will the three ACC teams that don't make the finals schedule games against Patriot League opponents, as has been the case in the recent past?

Seems stupid on its face. Supposedly this change has already forced UVA and Hopkins to drop their games in the short term because of how the ACC schedule works out.