By galaxy i mean solar system sorry.
SS = solor system
When a SS is tilted it can look like this

Yellow is the sun
The red line represent our normal plain SS. And when to go to another planet, you dont go up or down.
So if the SS is tilted, and you need to reach another planet like the blue line, its up or downwards.
So what im suggesting, is that some of the SS is tilted so we have more Z-axis movement.
And in a normal plain SS we we dont either move up or down, unless we order our ships to do so within a grav well.
So im suggesting that we get planets placed so we have to travel to the bottem or top or a grav well to reach the other planets. Something like SotS.
edit:
first post edited, so instead of galaxy i say solar system