From Kinkoid's website in a post called Attraction Presentation... read it on their website:

"Hentai Heroes is all about seducing amazingly hot fantasy girls and inviting them in your harem. It’s about that special feeling you get with each new gorgeous girl joining, that moment of pure joy and pride that she is joining your harem. That moment of sweet anticipation to start exploring her. All of these positive emotions sometimes get obliterated by the frustration of fighting too long with a boss or playing Pachinko without winning a girl. So during the past months we have been trying to figure out how to turn this issue into a feature and your doubts about the drop rate into excitement.
At the release of the game this system was fitting and was working very well, but as we keep increasing the number of girls in the Haremverse and also improving the game with new features, we are not satisfied with it anymore. Coming from that point, and listening to your feedback, we decided that we need changes.
We created Hentai Heroes to offer you, the players, a fun and positive game. And we are not going to risk the overall experience being negative because of a mathematical problem. We explored multiple options like putting a hard limit on the maximum number of fights you need to do before seducing a girl. Yet none of them were satisfactory and would be potential design limitations as the game continues its evolution in the future or would not be so easy to grasp at first glance. We wanted to create a system that would be a base to build upon; a system that is clear and will allow you to follow your progress by giving you an achievable goal.These are the 2 main reasons that motivated our decision to go with the Attraction. The principle is quite simple: each of the girls who are not in your harem yet, will have to be seduced by increasing her attraction to you."

You can read more of their blah blah on their website. Suffice it to say that not many players feel any of the warm & fuzzy shit they're selling above. This is nothing more than their greed... they are eliminating the "F2P" people and moving the game into a pay to get anything situation. Imagine you miss Fabienne, for example, and have only accumulated maybe 30 Attraction points. Then wait another 6 months minimum before she is offered again... another 30 points... another 6 months wait... another 30 points. I'm sure you get the picture and your feelings are nothing like the horseshit described above.

Combine that with the piss poor story telling that started in Heroes University & continues in Ninja Sacred Lands... they are doubled the story elements from all other worlds. You get almost no progression for high points spent... then waiting for "Coming soon" shit. I really don't enjoy the story element anymore.

This has prompted me to bail... after 2.5 years of great game, then ok game but I'm addicted, to love/hate relationship. I simply cannot afford this anymore... but mainly I do NOT want to support these fucking greedy devs and the sort of shit they put on us like the extract above. To all F2P players... make a stand and bail now as it is only going to get worse.