Wikipedia Zero proposed features
Proposed Feature List for Wikipedia Zero 
Web portal for partner management of Wikipedia Zero settings. 
Having a web portal for each carrier allows each carrier to manage their own settings, such as Zero-rated IP ranges, customized banners, and other options. This allows the carrier to manage their own configuration, and minimizes bottlenecks and errors of transcribing email requests from partners.
Some carriers do not charge their customers to use the home page. These carriers do not want a warning presented which may create doubt in the users mind about whether the carriers home page is actually free.
Right now, all of our testing involves enabling the Wikipedia Zero banners for the carriers IP range. Most carriers do not have an IP range they dedicate to internal testing, so any tests we conduct are prescheduled for a couple of hours during the evening. The problem is that customers are also participating in that test prior to the launch of the service. Since most customers do not want to be involuntary beta testers, we are looking at alternate means to provide functionality to only a subset of the users. Enabling this functionality via a preloaded cookie will give the carrier the ability to test the system on their network without impacting actual customers.
For marketing purposes, many carriers would like to have their marketing banner appear above the free wikipedia pages most of the time. However, this banner also impacts usability of the site on mobile devices with limited screen space. To balance these conflicting interests, the banner contains a close box which causes the banner to disappear for a period of time, currently a day. Please note that the option to keep banners shown is only available for the zero.wikipedia.org URL. Even if the carrier has made m.wikipedia.org available for free, users will always have the option to turn those banners off. This is important for people who want an option to use Wikipedia without banners most of the time.
Smarter landing page for complex font based languages. 
A carrier may support zero-rating languages that are difficult to render, such as languages that use Indic fonts. Until quite recently, most phones have not been able to render complex fonts, and that means that most customers would not be able to read these language options listed on the landing page (unless they had at least an iOS 4.0 or Android ICS device). So to avoid this problem, we are investigating ways to detect if the phone is able to render complex fonts or not. If we detect that the phone cannot display these languages, then the landing page would not list them on that phone.
More content on landing page 
The landing page currently only displays a search box and text links to other languages. There is very little to draw new readers in more deeply, and puts the onus on the user to take action rather than serving them content immediately. We should improve the usability of the landing page, by incorporating content sections in two to three languages. For example, the Wikipedia Zero homepage for India could have "Did You Know" from English Wikipedia AND Hindi Wikipedia, and also display text links the additional language home pages.