If I may add my input, your posts come off as extremely confrontational and demanding. There are politer ways to express what you are looking for in partners as opposed to "Here's what I want, my way or the highway."
In the link that you posted:
-First and foremost. ONLY CONTACT ME IF YOU ACTUALLY PLAN ON COMMITTING.
You could probably do away with this entirely, as it sounds a bit petty and elitist. Of course, we'd all love to guarantee our games will continue, but more often than not, we have little control over it. So instead, you could say something like "I'm looking for long term writing partners" and leave it at that, if you really feel the need to say anything.
Most of this part is fine, but it comes off as a bit desperate. All you need to do is stress the importance of communication once. There's no need to layer on all the justification. In fact, you could just say that you really enjoy communicating, and that will attract the type of people who do so.
-Spelling and grammar.
-Someone who's willing to help me carry the plot.
I've come to discover that I find people who explicitly vocalize these requirements to be somewhat irritating, simply because it comes off as saying 'you need to be good enough to talk to me.' A lot of what you are seeking here can be found by simply browsing someone's post history. As far as finding people who enjoy story developing, that's also easily discovered by communication. I've had people PM me with 'I really like this idea, do you want to do it?' and I'll reply with 'Perhaps, but let's talk about some of the details. Where do you see this concept going, etc.' More often than not, lazy players will simply reply with 'I'm up for whatever you want to do.' Someone more interested in developing the plot will offer ideas, suggestions, and scenes. Posting frequency can also be discovered through post history. If someone sporadically disappears for months on end every month with no activity, you may want to reconsider it when they say 'I want to plot a major, long term story with you.' I've had partners enter a game, then say "I'll post tomorrow" only to go inactive for 3 months...only to reappear in another thread where they say and do the exact same thing.
As far as fandoms, just be aware that you'll have an easier time finding games with themes people really enjoy. My hentai game was extremely popular because that theme and setting is extremely popular. My attempt to get a milf neighborhood game was not so popular, so it never got started. There's not much I can suggest here other than maybe explore and try some new themes and settings; that's how I discovered my love for the superheroine theme.