The site is about to let the users propose new designs that can provide different presentation and usability features.
How much of the site design the users will be able to control? That depends on the demand from the users, as well the viability of giving all the control to change what the users wish.
If you would like to change aspects of the site presentation and usability features, what aspects would you like to change?
Please try to be clear, objective, and realistic. For instance, do not ask to remove the site advertising, as it is necessary to keep the site financially viable.
Also read first the site FAQ - Frequently Asked Questions - to understand why certain site features are the way they are.
Thanks in advance for all the suggestions.
I think the best solution possible would be to recode the underlying html to be compliant code. With compliant HTML in place (even 4.01!), authors could create their own css style sheets to control the design.
As an example, take a look at http://csszengarden.com/ , and click a few of the links on the right. There is *one* html file, and all of the different looks and designs there are done with just css and image files. You don't even have to host them - people can use their own. Take a look at http://userstyles.org/ for examples of user created style sheets that anyone can use. There is even an "all black" version of phpclasses there: http://userstyles.org/styles/5385 (!).
With html valid code, your site will be accessible, will get better search engine crawling, and be more friendly to users.
Authors could even come up with mobile-compatible designs so you could browse phpclasses from a sidekick or iPhone.
Any good house building depends on a strong foundation. Start with html compliant code, and let css do the rest! (It could even save you bandwidth instead of costing you extra!)