As another poster pointed out, my product line, if the non-mechanics were taken out, wouldn't be a very big line. And that's the point. You don't buy the material just for the mechanics, and to assume that it is the only reason people purchase your material is actually somewhat insulting to the majority of gamers out there.
When you get right down to it, there's nothing that has been produced that a GM couldn't build on his own. The tools are there, examples are there, there's even step by step instructions on how to build everything from PrC's, weapons, magic items, spells, monsters, EVERYTHING!
When I bought various books, I did not purchase them for the mechanics. I purchased them for setting, fluff text, and details that are not considered OGC. After all, what is FR, Greyhawk, Shattered Lands, Year of the Zombie, Firefly, but just a handful of mechanics and a LOT of setting data? Pull all the PI setting data, and what do you have? Not a whole lot, when you get right down to it.
As for the Section 15, that's fairly simple to handle. A "variable form" that pops up, and insert the publisher name, the origin book, the date, and the author. One section 15 form, with the variable being buried in the data for the feat, weapon, vehicle, whatever.
As for cross pollination, no, you don't see much of it, but make no mistake, it's out there. I've asked for, and gotten permission, to be allowed to reprint Monte Cook's venom rules, I've been allowed to do a module for d20 Modern that crossed RPGObjects popular Blood & Guts line with my own just starting line, I've gotten permission from ENPublishing, Wizards of the Coast, The Game Mechanics, Ronin Arts, Green Ronin. Sure, it wasn't the whole book, often one or two small tidbits, but it is cross pollination. It's there, it's just not that blatant.
I look at the OGC Wiki like this...
It will happen. No matter what the majority of the publishers clamor. With "Crippled Content" being unethical at best, downright against the OGL at worst, the more publishers that move to it will not only alienate thier fan base, but other publishers.
Since it WILL happen, eventually, I'd rather be a supporter of it, and be able to control what goes into it from my writing, rather than it just being added.
On the format, I would want to see ALL flavor text/non-mechanics data pulled from an item going in. Just straight mechanics and nothing else.
No maps. No fluff text. No character names. No non-mechanics information at all.
[Feat name]
[Benifit]
[Special]
That's it.
With the presentation handled correctly (The item being looked up, with the section 15 at the bottom relating to that item, and the banner for the company that produced the item at the top, along with author name and publication of origin underneath the banner) it would not only generate interest, but clearly and definately show who the work belongs to, who came up with it, and where it is available.
Seeing the different ones, say, Paladin classes, also allows a browser to decide which versions of Paladins he likes better. And a book about Paladin classes is going to have much more desired data than just some variant Core Classes and some PrC's, it'll have non-OGC information out the wazoo, and that will allow the browser to also decide which one he wants.
Face it, the person who just goes there to get data, bare bones mechanics data, is more likely to get the PDF from a P2P network than to shell out $7.50 for it. They aren't the ones the site would be built for.