is there any indication that the uptake for custom CSS has budged from 0.1% of all users?

It’s probably down. Early adopters were more likely to buy the CSS upgrade than people who signed up later. Plus the site is accumulating more and more dead blogs; the last news post of supposedly impressive stats puts the percentage of ‘active’ accounts at 25-30%, and that’s with a very generous definition of ‘active’; the proportion of blogs which are actually being posted to must be substantially lower (or he’d have used that figure instead).

If the figures for custom CSS were anything other than mildly embarrassing, they’d have found their way into Matt’s marketplace announcement as proof that there’s a market for paid themes here. But then, if custom CSS had worked out, he wouldn’t need to resort to selling ready-made themes at all.

matt’s explicitly said that the marketplace and the allegedly forthcoming themeviewer will run on the same code

They will be one and the same, won’t they? He’ll use the complaints about outdated themes as an excuse for wiping the existing database and starting from scratch with the profit-making wp.com submissions. It’s the only course of action which gives him the requisite level of control over quality, licensing, security etc. Running two entirely separate repositories would make no sense. There may be some grumbling about the GPL requirement and the ban on linkbacks, but I suspect most designers will be willing to trade in their rights for the prospect of .com pennies. Bullying may not have worked, but bribery might.

As for the plugin issue, that’s because Matt doesn’t have the time to approve the volume of submissions but refuses to delegate the gatekeeping on .org to anyone else. He needs to get over that sooner rather than later. It could be a deliberate policy to deter contributions from outside Automattic, but mostly these things are down to incompetence rather than Matt’s Master Plan of World Domination.

Someone was expressing their annoyance on the wp.org forums as well a few days ago about the plugin database being unaccessable as well on wp.org. That and getting plugins approved in a timly manner or even at all has been an issue for quite some time as well.