Hmmh. I've advocated for more nuanced content warnings here on Lemmy. Didn't resonate well with neither the community nor the developers. I dropped the topic. I'm waiting for PieFed to come along and bring me an alternative backend for the Threadiverse.
Thanks for the summary. I don't really use Mastodon so I wouldn't know. But I'm all for alt-text to images. I set them on every website I'm involved with...
I'm not sure about Lemmy. I use this more for textual conversation. But now that I've learned how to do it in Markdown, I'll add the description to the 5 (or so) pictures I post every year.
I don't think other places on the Fediverse have a distinct culture or vision. Like Mastodon has. For example Lemmy is quite random. And still dominated by the lots of ex-Reddit-users who migrated here. And we often can not agree on where we'd like to go. And I perceive a split/separation between the developers and the users. There isn't really a conversation going on. Neither between users and developers, nor between the users themselves. So my prediction is: As of now we're not going anywhere. Lemmy is going to stay relatively random and will also stay about the same size, until someone steps in and changes this place.
Do you have a vision? Is there a reason why you started this conversation? Something you'd like us to do?
(I mean you could post your comprehensive perspective in a post/thread here, and then also toot the link to Mastodon, or boost it or whatever that's called. I think this is just a meta discussion and it's probably not going anywhere... You got a bit of attention here, but ultimately we're still not discussing the actual topic. At least I didn't yet understand if you have a need or a proposal to make.)
Oh well. That's a bit more complicated than I thought.
First of all, it might be true that people here won't understand you. And I'm not sure if Lemmy is the right choice for you anyways. The OpenSim community doesn't seem very active. And since you're talking about 13.000 character descriptions... That will also not fly on Lemmy. I think we have a 10k character limit for posts and comments here. You'd exceed that here, too.
And then Mastodon is a microblogging platform. Originally intended for short messages. I know some people use it for a different purpose. And some people go there because of the short and concise messages. So I'm not really sure if that's your place either. It might be you using the wrong tool for your task, since it's intended for a different purpose and you'd need a different tool.
I mean I don't know where the community of 3D worlds mingle... Maybe you can take some inspiration from them if you're not the only one.
But it could very well the case that the alt-text and character limits of the platforms aren't the issue here. But you choosing platforms that are not suited for your task. I'd say if your texts regularly exceed a few thousand characters, you don't want a microblogging platform, but a macro-blogging (or just blogging) platform. There are some that are meant for long texts. And you can even use Wordpress or something like that, do your own blog and install an ActivityPub plugin if you want a connection to the Fediverse. I mean in the old times, people used more than social media and shared their thoughts in forums or on a personal blog, or a website dedicated to a topic. That comes with almost no restrictions.
Ultimately, I haven't seen your posts/toots. And I don't really know the alt-text culture on Mastodon. Maybe my advice isn't that good.
Another thing: Is it really necessary to write that super detailed description in an alt-text? As far as I've learned about alt-text in webdesign, that is originally intended to give a concise description of the image in the context regarding the rest of the text. It is meant to be short and concise, like a tweet. It's read by screenreaders and displayed if the image didn't load. It'd be more something like: "a medieval market squares with dozens of booths, bustling with player activity." But you won't describe what's sold in the market stand at the bottom right, or the portal on the left, unless it's important in the context of the rest of your post. If you want to do a comprehensive analysis or a discussion like in art class, I'd say that goes into the main body text, and not into the alt-text. I'd consider that "abuse" of the alt tag. And it might even do a disservice to people who need accessibility, who now get a completely different experience than everybody else. I'd put that detailed description into the normal text. Maybe make it a spoiler so it collapses.
In the end I'm not part of that community, and everything depends on what you're trying to achieve. But that'd be my perspective: A blog would be better suited. And long descriptions go into the body text, not the alt-text. And if you choose to write longer blog posts, you can still link them on Lemmy, or post a link to it on Mastodon.