Is it just me? Or do most people feel like devs promissing a spin-off or starting a completely new project while having the base game unfinished is a bad idea.
It depend. If it's effectively a Patreon goal, it can perfectly mean that, starting this amount of money, he will hire someone to do part of the works for him. Therefore this will give him the time to works on a second project, without really impacting the first one.
At least theoretically, because in practice when you works on a game, especially when it's your game, you pass most of your time thinking about it. And switching between two projects only mean that there's a big mess in your mind.
I feel like there's some inherent contradictions in the Patreon model of tiers.
Have to be kept in mind that it's a "one fit all" model.
I agree that it seem to works backward regarding game production, with, like you said, what should be free being the reward for high tiers, while what should cost the most is the reward for the lower one. But in the same time, this model works way better for almost everything else, because the reward is then something totally different from the product.
In a way, it's the faith of the profession. Anything you can offer as reward will seem to come directly from your game, or it will lower a bit its interest.
You offer pictures ? Well, even if your game is in real time 3D, aren't "good and lewd visual" what your game is already offering ? Then, as you said, those pictures feel more like promotional material than rewards ; "Yeah, you took a screenshot of the game, is it that ?"
You offer exclusive in-game content ? Either it will be something disconnected from the story, in which case does it really worth it ? Or it will mean that a part of your game will be unplayable by those who aren't your patrons. And then, will people want to be your patron, if the game they tested for free is deprived of what is probably it's best part ? It's like a cook giving the full meal only for those who pay an additional fee. Some will be curious and do it, but the majority will try the incomplete meal first. Then, like it will be something totally average, they'll believe that the full meal don't worth the additional fee.
Even offering early access related to the tiers do not works. Whatever if you have to wait 0 days or a full month to have access to the last update. In the end, you'll still have to wait two months (by example) between two updates, whatever if you're at tiers 3 or tiers 1. It's just that those two months don't cover the same period of time. It don't even works the first time, since you'll wait for the game to be available for the tiers you want to join before you starts pledging.
And of course, the access to intermediary update is the worse. If will feel like you are paying for the right to help the dev debug his game ; "hey, pay me more, and you'll have the pleasure to play unfinished updates with bugs and placeholders".
So, what left exactly for game creators ? Not much except commissioning someone to create totally different content. But most creators on the scene don't earn much. Therefore, they'll loose more money doing this, than they will gain. So, in the end, they do with what they can...