I am doing some research using the Game engine ioquake3. We were able to reduce the processing time to a certain amount while maintaining the Game's sanity.
As a next step, I am looking for ideas to benefit from this additional CPU space. I want implement ideas that would prove that this additional power is beneficial. Currently, I am reading in these forums to find some ideas for it. So, I thought why shouldn't I just ask and see what answers I may get.
For example(this is just off of the top of my head, so please don't focus on this example), with more CPU power, you would have the possibility for bigger maps with more players. This should open doors for creating more diverse style of play-modes, such as King Of The Hill...etc
The steady march of hardware means that additional performance is essentially free over time, notwithstanding other bottlenecks. This, of course, is not to dismiss your optimizations, I just think that your thesis has an obvious conclusion (free up a finite resource, and you can use it for other interesting things).
It applies to fixed-platforms like game consoles or embedded devices, but the ever evolving PC platform is a moving target -- essentially every time Intel or AMD speed-bumps their CPUs, or AMD or nVidia introduce a new GPU, you can do a little bit more.