Sure maybe I'm wrong. But I've seen so many games start off strong then after a while the dev can't control the direction all of the various characters take the protagonist and the story ends up being random stuff happening just to shoehorn in developments for characters the dev hasn't worked on in months. I've stopped my patreon support since the previous update and really happy I did after this most recent update plus I saw 3 other people in the patreon comments saying the same thing. So I know I'm not the only one
Variations in opinions and feelings. As someone who sponsors on Patreon, I understand your decision, I have seen that happening.
There is even a big outfit (they get 14k a month on Patreon) who recently celebrated a 6 or 7 years on their game and even say explicitly they built a company, yet aside webcasts, their speed in new content is slow (although admittedly not using renpy, but I could not avoid noticing the version of the engine they use is "personal"). It's true that the amount they got probably increased over time, but otherwise, 14k*12 months in year*6 years, it's more than the budget for a big (complete) game, and they show no intention of ever completing it. That is a milking machine, the only reason not to stop it, is that even the lower levels get access to the game, and I am in one of the lowest levels. But it seems pretty clear aside the "money milking", they improvised in many aspects.
This brings to Zorlun, and why it seems the same things that make you skeptical, convinced me to do the opposite and become a Patreon (although it's true I also had a chat with him to confirm my impression).
What Zorlun has done till now, is trying to build up the character roster, but instead of throwing them just list a list of characters, he has introduced them as part of the story arch development (and the development of the characters themselves) creating a context.
He mentioned there will be maybe a couple more, as well as a couple more potential "places" that will come up, but in any case, he is not really improvising the main elements - for the main elements, he has already the lines, it is only details and small things that can change. For the secondary scenarios (e.g. the weird events), he could improvise more, but than, if it they were all pre-planned in detail, they would not be weird events ;-)
It is still possible he may underestimate a bit the work needed in some parts to keep up the branching ? It is.
Could that have an impact in future ? Yes, but given the he has things planned ahead, even if that happened, it would probably only mean that instead of an update a month, it would take a bit longer for the update, or some future updates would be focused on certain paths.
It is never impossible that a game gets abandoned, but it highly improbable that will happen for this game, at least not due to the "too many paths" or "too much work".