Weed out spam applications during certification process
The amount of spam applications, apps that are split out into several regions (i.e.: MyTranspo series), the ridiculous feed readers for all different musicians and whatnot, single book applications, and do-nothing apps (i.e.: the stuff published by "Eric_rulz")... This is just absolutely ridiculous. You already promised to take care of this, but it didn't work. We've still useless applications flooding the Marketplace, and there are no signs of it slowing. I believe that, instead of limiting the amount of certifications per user per day, the Marketplace should be a little better curated. Spam applications should not be approved. They should never pass certification, and should never be published. Bulk publishers should be made to consolidate their apps, and the rest should not pass.
I was going to suggest giving each user their own personal "ban list" to blacklist publishers they don't personally want to see anymore, but that's probably something only a few of the more savvy phone users would actually discover and use. I think I have to agree with the OP that a more rigorous screening during the certification process to prevent these apps getting published in the first place is the only thing that will really work.
I hate working for months to make a quality app that actually does something only to see it pushed down the New list by bulk-published do-nothing app clones.
They aren't even trying to be stealthy about it because they know nobody's looking. You can easily spot a dozen cloned app icons in a row in some marketplace listings.
It's bad for devs, and it's bad for non-dev people browsing for apps. It makes the marketplace look like a city landfill.