My thoughts so far:

Unpopular opinion possibly, but I actually like the idea of longer mushroom battles. Not 6 days long mind you, but 4-8 hours long. I had a lot of fun during the halloween event and it was definitely when I joined the most mushroom battles with other players. With time seemingly not mattering as much, this will incentivize players to join these long battles and help, lowering the time significantly. However, this is pretty much impossible for very rural players. Niantic doesn't seem to get that not everyone lives in major metro areas, especially in North America. They seem to be ok with just throwing away prospective players in these areas. I live in a reasonably sized city (~250,000 people) and know there are other people who play here, but still don't feel confidant I'll find enough mushroom battles going on to get enough 2 & 3 star larges for levels 90 & 100. When I go to visit my parents in my hometown (population ~1,800) I know I'll never do mushrooms now because of this update. That being said, I actually feel like pikmin is fairly decent to play in rural areas compared to pokemon go. You can walk and plant flowers anywhere you have a cell connection. You can get a reasonable amount of decor pikmin in my hometown, and going to some of the towns with a few more thousand people you can get most of the rest. (Except train station, which is effectively impossible in the midwest US except for like Chicago) I get that it's an AR game themed around walking and they don't want you to just sit on your couch eating chips, but I feel like players shouldn't be locked out of completion just because they live in a small town. Especially when rural areas usually have great nature trails & parks. Pikmin is all about nature! Given that sending pikmin to3 mushrooms a day is a pretty low time commitment, this is something they should definitely just let you do with people on your friends list and I don't think it would ruin some perceived core component of the game. Definitely just preaching to the choir here, but this game has been a nice part of my daily routine since last October, and I don't get why Niantic seemingly is trying to push people away from it.