For audio personnel, pre-production is typically a very quiet time on a video game project -- perhaps being involved in some "look and feel" movie material for greenlight meetings is the extent of the workload.
However, getting involved in the game design work is fundamental to integrating audio into a game. Try to re-conceive of this as your most productive and collaborative time on a project, a time where lots of different ideas can be tried out, a very experimental period. There are several ways that audio can be brought into the game development process at an earlier stage:
Ensure that sound is clearly represented at all the pre-production game design meetings, particularly early story concepts. Think about how sound will change over the course of the game.
Ensure sound is present at all early technical meetings in terms of art pipelines such as animation. Sound should be considered technically as an integral part of any art asset or any animation pipeline. In dialogue, consider driving character animation from sound, rather than having to retro-fit sounds to match animations, which is frankly impossible in terms of dialogue content.
The direction for how a character looks, sounds and feels should be a collaborative direction invested in by everyone involved in its creation, so being involved in concept art for major characters is also a great place to get ideas moving.
Be present at storyboard meetings in order to have input on how scenes play out, work closely with the DP in allowing opportunities for dialogue to feel natural and also allow for the characters to hear things and interact with sounds within cinematic scenes.
Be in as many game design meetings as possible. In essence, at this stage it would be most beneficial to be considered part of the design team by the designers. Consider sound as part of any gameplay device or feature, and how it functions. Always allow for, and state the case for, sound to lead the gameplay.
Be proactive! Get out of the studio. Remember it is very rare for game designers, animation artists or others to come to you looking for your input on the design of a feature. They usually only find your studio when they need something from you, i.e. when they have already finished the art or design and now need you to make it sound good. Take a laptop and sit among the game designers or artists for a few weeks, be visible on the team, become a familiar part of their production environment.
Foster a collaborative environment. Most importantly, remember games are not there to satiate the sound designer's ego! Great sound cannot save a terrible game, so being mutually accountable for the work of the rest of the team is critical.
As a sound artist you are collaborating with producers, artists, coders and designers in getting what is best for the game, so be prepared to listen to others' opinions and try out their ideas, as well as expecting others to listen to yours. Next generation offers the developer nothing if not the chance to work with greater awareness of other disciplines.