I liked he idea of hyper space waves and the hyperspace terrain in general.
Perhaps with the hyperspace waves you could have them as intermittent wave events that spread out radially from stars, this allows a player to ride the wave in any direction they like. Radial textures increasing in size can be difficult to do though...
But you would be able to make waves visible inside and outside of hyperspace by having the wave generation events from suns effect the luminosity/colour of the sun. So in the 30 seconds to a minute or whatever leading up to the event there is predictable and easily observable changes giving the player some warning to if they want to jump on the next hyperspace wave.
By having the waves generated from stars and having them on a regular or predictable basis it would be easier to program Fleet AI to take advantage of these events as you could check the star's 'hyperspace wave generation' timer and determine when best to move through a jump point and exploit the wave.
Had a similar idea, actually, with a slight twist - basing wavefronts on solar flare activity. The issue here is, why wait for a wave? If you just go, you'll catch it whenever it catches up to you, if it does. On the flip side, you might have trouble approaching a star if you keep being pushed away by 360 degree waves. It's a neat idea, but it doesn't seem to do the job by itself.
Yes I was wondering about solar flare activity myself after remembering the new effects you've done for stars.
So let's address the two gameplay issues behind the implementation.
Why wait?
By drastically reducing fuel usage the closer you time your wave surfing to the event and adjusting fuel pricing accordingly you can increase the value of timing your departure. Being there at the start of the wave will save you more fuel, when you have big fuel hungry fleets with lots of tugs it can save you thousands upon thousands of credits.
Next you could look at wave surfing or the wave providing a boost before washing past you. So if you catch the wave closer to the source you get a bigger boost for longer before the wave outpaces you, compared to going ahead of it.
As for approaching a system that has outgoing waves, like I said the wave is not a wall and has a degree of permeability, the degree of permeability will depend on your orientation and vector to the wave. Taking a real life analogy if there is a large wave coming towards you, you point the nose of your ship toward it and power over it - potentially using the fleet engine boost command/ability.
In the game best case if you are pointing your fleet perpendicular to the wave origin you will be paused momentarily as the wave passes, worst case is if you're between 46 degrees to a tangent to the wave front and your fleet gets CR reduction, fuel increase or possibly damage.
On the flip side if your ship is facing directly away from the origin you save fuel and get a speed boost as the wave moves past you, and as you change the facing of your ship away from this by up to 89 degrees you use more fuel BUT the wave will carry you for longer as the 'friction' between your fleet and the wave increases -thus allowing you to 'surf' the wave edge
To stop riding the wave you turn away from the wave front and let it pass over, or maybe use the fleet engine boost command to quickly turn and ride over it.
It would be a bit of a pain to get right and adjust all the parameters for the boost given by the wave and having the ship interact with the wave front etc. and the fleet AI...oh *** snacks...yeah that would be painful to teach a fleet how to surf. At best with the AI they'd know to face into the wave and hit boost?