It doesn't have to be that complicated for WOTC to get better products out of the third party publishers.
1) Have legal requirements (like now) that set out expectations of the product's standards
2) Include the design documents that the in-house team use and require it to be used with any materials that are created for 4e. This document should be all of the inner workings on balancing feats, skills, magic items, etc. Including commentary from designers (like what you saw in the Rules Compendium). Examples of good and bad rules. Layout what sort of stuff should be avoided and why. Give step by step considerations to building mechanics properly. Lock this stuff down under NDAs. Keep the clause of you can't tell them how to generate stats or level the character. As it updates, publishers get those updates. These documents exist inside WOTC right now, always have, and 3rd party publishers should have accesss to them somehow.
3) Then require certain production standards and tradedress expectations for black and white and color products. Keep these somewhat loose, but clear enough that companies can put that D&D look on them. Just like a Wii, Xbox or PS game has trade dress. This document exists for D20 Modern in a roundabout way, the modern d20 liscense actually states what a 3rd party publisher can't do with graphics (i.e. copy the dark red and metallic look of modern's books basically.) You can do something similar to allow some visual compatibility between products, like a spine and side bar, certain ways information is presented in the stat blocks and game mechanic layout, what fonts to use or not use etc. Just so there is constistancy in design.
Once these things are done, WOTC has a tight package that requires no further up keep. A company pays for the developer package, signs the NDAs and they are off. They are responisble as they are now with keeping themselves compliant. If WOTC finds out that they break a rule, then the publisher has to pay to fix the damage, as it is now. Simple.
WOTC could offer editors to check for compliancy at a fee, potentially. But, that seems unecessary. I know that some industry names, like Ryan Danacy, are willing to do services like this if you ask, with their fee varying by the size of the project.
Right now, this whole OGL thing could be a repeat of what occured before or we can take the opportunity to learn from the mistakes of the d20 brand and fix it. The main issue was the lack of quality control. So give a better quality control system to the publishers willing to pay for it. The rest can publish under the OGL without the d20 logo on them, and without teh compatibility language. Simple.
Alot of you are acting like these materials are difficult to produce. Truth is, most professional companies do this stuff all the time, WOTC being one of them. It is the reason WOTC is so much more professional and consistant over the other companies. These materials already exist for 4e, I guarantee it. Some of those materials would help these problems and draw a clearer line between the good and bad products out there, and D&D can grow and benefit from sharing those developer tools.
