To sum up some of the issues and solutions people have stated and suggested:

Affection scenes are too expensive, especially for older players with more girls. It's not reasonable if a girl costs more than 5 million total including the items you use to get her to 3 stars. An upgrade should never cost more than 100+ days to earn back with the bonus it gives, and certain upgrades take years to earn back with the current uncapped scaling prices. As such, there should be a cap to the prices in both affection points and money, as to not overwhelm people with the currently rather extreme prices and a single step should never cost more than 2 million total (which takes more than a year to recover already).

Girls in general are also more tedious to manage, with reduced times between collections for all girls and decreased collection rates for non-event girls. All girls except a few are now a uniform 1270 currency per hour, and a change to this might help.

Item values in the shop have inflated a lot, while the sell prices are way down and essentially making the items worthless to have and hard to obtain when you do need them. It's also impossible to get boosters for free and it requires the spending of Kobans to get them now. As such, the prices on both ends should be readjusted somewhat, although not necessarily to the previous levels. I suggest a 25% decrease in buy price and a 100% increase in sell price for common and rare items while increasing the buy price of epic and legendary items by 40%. Changing the Koban costs for boosters in the shop back to normal money may also be a good idea, seeing as they only have limited usefulness.

Bosses no longer give experience, and this is weird considering their cost in energy and the fact that arena battles do still give experience AND increased money. PvP also lacks any real incentives and competition due to it's current system, and that was unfortunately not fixed with the update. Adding exp to the bosses and adding an incentive to PvP would increase interest in the game as it rewards their respective forms of activity.