I really enjoyed the recent Maze event. It felt like the perfect event for players stuck at around 200 - 220. After playing for about 60 days, I have some takeaways.
First, there was not enough dust, specifically green and blue. The maze event required the promotion of heroines to keep progressing, and I ran out of blue and green dust to use with normal and rare heroines. Yet the prizes gave me more yellow and red dust than I could ever use. You need so much green dust to use the normal heroines, and you need so many SR heroines for every promotion level. This meant I couldn't promote Alice even though I had more copies of her. Maybe allow higher quality red, gold, and purple dust to substitute for green and blue dust, with higher rate dust worth more?
SSR heroines are useless after level 260. It is extremely rare to pull them, and the promotion requirement of having a 12-star SSR heroine to use gold dust means it just isn't possible to ever promote your SSR at the same rate you can promote UR. You need like 18 copies of an SR to move from 260 to 280 (and every step when it asks for a copy of your upgraded SSR as a UR), when you should only need two copies and 1000 gold dust. You are more likely to get enough copies of UR heroines than enough copies of SSR heroines to promote and use past level 260. Note that this also effectively stops SR, R, and normal heroines from mattering in the end game. Their only use becomes promotion fodder for the UR's. SSR can't help with promotion, thus useless.
The store offers are not useful since you need many copies of a heroine to consider adding her to your team in the later game. The only way to make the store worth it with only single copies is to also add a skin of the heroine since it is next to impossible to get those in game.
I would very much like to know the heroine's name when I participate in a journey, campaign, or other mode. If I hover my mouse over her, it should display her name. This helps me figure out who should later go in my party. It would also help players spend money because they would know who to buy.
There should be a fast promote button for oblivion and even when moving out of the academy. I do not enjoy clicking hundreds of times to promote a heroine from the academy because she has caught up with the main six and can overtake them in level. I want a button in Oblivion to add 10 levels at once.
Finally, several areas of the game refer to the heroines as males, such as the heroine reset area and Kiko's six-star ability. Please make sure your game refers to all the heroines as female.