For me it is not a downgrade, before the dialogues were all random and sometimes I wondered where she came from with some dialogues, now you decide what to talk about or there is an option for random dialogues.
The topic thing itself is fine, I'm referring specifically to the new "respond" option, which is even more random and nonsensical than it ever was in KK.
Now instead of getting a weird question and choosing between the only reasonable responses, I get asked about teddy bears and can only respond by talking about fucking fiddler crabs? Then when the next girl asks about fiddler crabs, I can only stare in fucking silence because all my knowledge of fiddler crabs was consumed in the last conversation?
The whole idea of consumable topics is fine so long as you can abstract it away as the gathering points giving you some experience or insight relevant to the subject to relate to the girls. You can only use them once because trying to have the same conversation with multiple girls on a small island just makes you look like a poser or something.
The moment I have to respond like an idiot to a basic as fuck conversation prompt because my topic points have run out, the system collapses. I can't even pretend the topics are actual topics, they are now magical "relationship+" items with their own special rules completely disconnected from reality. They might as well be different colors of fairy dust at that point, in fact that would make more sense.
If Illusion was still in the business of making actual gameplay like they did with AA2, there's all kinds of things you can do with this system. You need to get a topic only once to have it always available: each gathering spot gives you an extra star in the relevant topic: using the topic consumes one star, and using a topic with no stars (abstracted as you having nothing interesting to say on the subject and being boring/awkward) results in negative/no approval, UNLESS its the correct response to a prompt, in which case no star gives tiny approval and more stars give more approval than if used normally, maybe stars arent consumed when used correctly in prompts as well.
Thus instead of being complete random bullshit that makes your character look like a retard 90% of the time you use it, the prompt option is a payoff for your investment in exploring the map and gathering as many stars as possible in all topics, while also cluing you in to the topics the girl likes, so you can use them normally if you want a guaranteed decent approval boost, instead of risking a prompt for a no/low-star topic. Getting a prompt for a no/low-star topic is now at worst a clue to what the girl likes, instead of almost always being little more than an indicator that your character has crippling damage to the speech center of the brain.
If you wanna go to the next level, you could get xp in each topic every time you hit a gathering point, or maybe only when used correctly in a prompt. enough xp and your stars for each topic can only be consumed to a point; you'll always have at least 1-star, 2-stars, etc. emulating you getting enough experience on the topic itself and how to use it in conversation to always have something interesting to say on it. We'll make girls' preferences have more impact in return, so you still have to know what the girl likes to talk about to really benefit from a maxed out topic. Xp should be gained slow enough that you can only max out all topics after hours upon hours of exploration; you gather a few topics each time period, slowly building up knowledge useful to your lustful machinations, only getting max topics after you've done things the hard way with most girls. A little bit of character progression here and there, actual engagement with SOME kind of conversation system instead of just mindlessly hitting whatever for each girl until they inevitably fall in love with you... that would go a LONG way.
Had enough yet? Not me. Let's give the girls their own xp levels in all the topics, or maybe topic categories (or both), editable in the maker like any other stat. The higher their level, the higher YOUR level has to be to get any benefit. This can be separate from what topics the girl actually likes; she can know a lot about a topic but still not actually like talking about it, or have a passion for it and appreciate it all the more when you can discuss it on the same level, or know nothing about it and not give a shit about it either. Now we have a whole new dimension to their personality without complicating the gameplay at all; you're still using prompts and topics to see what works for each girl, there's just more possible permutations to their tastes, making each girl feel more unique.
Given what's already been done in AA2 and the fact that everything I've presented is relatively easy to code and off the top of my head, the fact that KKS's simplistic, weird meta bullshit is what we got is quite disappointing. I can only hope more japanese people come to this site for illusion games instead of paying for them and force the company to start fucking trying again, but there's fat chance of that any time soon, so I'll keep dreaming I guess. They still provide better sex content than most actual women these days, probably doubly so in "land of the permanently unsatisfied battle-axe wife" japan, so I can at least understand why they have no pressure to improve.