What a wonderful idea, Pandorum. I admire your ingenuity and drive.
I'm sorry in advance if any of this repeats others' suggestions. I only skimmed the preceding responses.
I would say one very important consideration would be the cost of membership. Dating sites aren't cheap to run, but for a community with many un- and under-employed members, a site shouldn't be costly to join, either. You will want to pre-consider what sort of advertising you would deem acceptable to your audience, and research how much you would need so you don't wind up in the hole.
You might want to consider adding a private conversation feature to your site, much like the one here at AC, so members would have a way to get to know each other a bit before exchanging private contact information, never mind meeting. I can't speak for all Aspies, but for me, having the chance to exchange letters before taking things further would be very reassuring. You would need to find out what this would do to your liability, however, and consider what role you might have to play as far as addressing problematic exchanges that occur on your site. You could find yourself having to ban paying members, among other potential problems.
Because we Aspies are very complex people, you would also want the options for describing sexual orientation to be very broad, and add profile questions about things like preferred living arrangements, and problematic stressors like crowds, loud noises, etc., to help members identify people who would be most compatible in ways NTs would not generally require. A section for identifying special interests (separate from other, less intense pastimes), co-occurring diagnoses, and how AS diagnosis was reached (self v. doctor) might also be very useful for members.
The question of allowing NTs who are interested in meeting an AS partner is one you would have to consider carefully, as some of these may indeed be predatory. If you don't want NTs to join, you would have to be prepared to refund any fees paid up front.
Since you wouldn't be in direct competition with any existing dating site, you could probably get some very good advice from the owners of some of the smaller existing options. The best advice for any new business often comes from those who have done something similar. There is a dating site for people with mental illness,
No Longer Lonely : Online Social Community for Adults with MentalIllness , that might prove useful to review, or good for a chat with an existing site owner.
Hope this helps. Again...
great idea!