Cycles aims to be a render engine for individuals / small studios, aimed primarily at rendering animations. This goal is what we evaluate priorities of features by.
For 2.75, the following features are planned to be worked on:
- Memory and performance optimizations
- AMD kernel splitting
Beyond that, there is a feature list which contains other small and bigger features we'd like to add eventually.
If you'd like to help out, you can look in these places:
If you need more details about how features should work, how to implement things or just to announce that you're working on something, contact the bf-cycles mailing list.
There are some things obviously missing that people would like to see added. Bidirectional path tracing, photon mapping, MLT and similar algorithm are not a priority for me, since we do not believe they are the main possible performance improvements for animation frames.