The legacy problem with NG is the majority of content is Flash-based so it has never been a smooth transition to mobile platforms. That's all changing over time and with updates to the system but it takes a lot of work and as usual our team is really small. Examples of things we are doing:
1) We are releasing free software that makes it easier than ever to convert SWF to MP4 with the best quality ever. This means artists and moderators can create MP4 alternatives for a majority of the movie content from the past 12 years on NG. Our project system will offer the ability to upload an MP4 alternative that can run on non-Flash devices.
2) We are setting up a server to compress MP4 files on the site to more mobile friendly sizes. Right now our emphasis has been on 1080p video for desktop and TV but those files are a bit big for mobile viewing.
3) We will soon be accepting games in HTML5 format and will also allow people to upload HTML5 alternatives to existing SWF games. If someone makes a game with Stencyl 3.0 when it comes out (soon), they may want to submit both an SWF version (spreads virally to thousands of sites where they can make revenue from the built-in ad) and an HTML5 version (to work on mobile).
4) We will ultimately need to make the site html more adaptive so that it adjusts to mobile devices. For example, not load the heavy page skins, reduce the header height, make text bigger, maybe even move the entire left column to make content buttons fill the width of the screen.
We could also have unique pages built for mobile but I really prefer an adaptive design so we don't end up with two unique websites. We will also need to make our content pages filter based on platform, so if you browse the games page on an iPhone it will default to an HTML5 game filter (with toggle options in case you want to just check on stuff).
5) While not technically a mobile feature, our upcoming feeds section should make it easier for people on the go to keep track of their reviews, forum replies, etc.