Peter,
I think your list is very informative. I don't think this topic is pointless; I view it as a very straightforward, basic guide for beginning and intermediate aquarists.
Everyone has valid suggestions, especially about adding more detail ie why the particular fish should be avoided. But I like the generality of your first list--it's a very basic guide, a quick reference, and I believe it will help guide people in making more responsible decisions as to what they should try to keep in their tanks.
I believe you should make a much more detailed list, including the arguments (for lack of a better word) that long-nosed hawkfish are very hardy fish, but they are known to be jumpers and so just make sure the tank has a tight-fitting lid; or that certain species of lions are venemous but can be successfully kept as long as you don't touch them, and if you do, it'll be like a bee sting; or that most--if not all--triggerfish can be kept with tankmates as younger speciments but will absolutely, without a doubt need their own tanks as they grow and thus should be avoided.
My long-winded point?
Just make two lists! Your extremely generalized one, and one explaining in detail the reasons for the generalized one. The first one serves your purpose greatly of being used as a quick reference or something to keep in your purse or wallet to refer to, while the extended version could be accessed to answer more direct questions about the actual specifications and "why shouldn't I keep this fish?" questions.
I'd be more than willing to help you if you think this is a good idea. I'm definitely not your expert by any means--more of a low-level intermediate at best--but I can probably help put things into perspective so people will get it. [This huma huma is adorable when it's young, and none of your other fish will fit into its mouth, YET, but it will absoluetely need a 200 gallon tank as an adult with NO other tankmates. If you like fish with teeth and you want to keep it in a reef, consider a royal gramma basslet.] Hah...like I said, I don't have a fantastic array of knowledge and even less experience, but maybe I can help with something.
In any event, I think you have a great idea here and I think you should stick to it. Whether others think so it not, it will help (and has helped!) many people with their livestocking decisions.
-- Nikki