Body-Fixed Reference Frame

[natsirt721]

The map view should have a toggle button to switch the reference frame from which trajectories are drawn.  The current mode (body-centered inertial) is great for visualizing orbits and keplerian mechanics, but a body-centered body-fixed frame would provide some additional information.  For example, landing on bodies you would be able to set up a retrograde maneuver and see your exact point of impact.  For synchronous orbits, seeing the anelamma can help with precisely establishing an equatorial synchronous orbit.  If I have a relay in a highly-elliptical orbit, I can see exactly when it will pass over points of interest on the ground

IRL, converting from ECI to ECEF can be a bit of a challenge, but the simplicity of Kerbal's physics engine should simplify this to a just a transform based on the body's rotation rate.

Additionally, there would have to be some setting for how far in the future to visualize the orbits, as they would no longer be closed conics but rather arbitrary paths.

[Gargamel]

Not 100% exactly following you, but from what I can tell, you can already go to map mode, hit Tab, and it will cycle between the planets, with that body as the fixed point.   Hitting ' (~ key) will return you to your vessel. 

33 minutes ago, natsirt721 said:

Additionally, there would have to be some setting for how far in the future to visualize the orbits, as they would no longer be closed conics but rather arbitrary paths.

In the settings, you can change the patched conics limit to a higher value, letting you see farther into the flight path. 

[natsirt721]

The default path mode, body-centered inertial (ECI)

https://en.wikipedia.org/wiki/Earth-centered_inertial

The mode I am suggesting, body-centered body-fixed (ECEF)

https://en.wikipedia.org/wiki/ECEF

The difference is that the latter takes into account the rotation of the primary body.

[The Aziz]

12 hours ago, natsirt721 said:

For example, landing on bodies you would be able to set up a retrograde maneuver and see your exact point of impact.

Perhaps this is what you want 

it does that and much more

[natsirt721]

Ooh, that is very nice,  I'll have to take a look.  I maintain that it should be stock behaviour.