Right. Patched conics do model slingshots.Raph Koster
has written a bit on this topic. The short version is that players don't give shit how clever a programmer or their code is.
Here is a slightly different case: Someone made a spacegame that he wanted as realistic as possible. Instead of classical newtonian he went with always using einsteinian gravity modeling and red/blue shifting and other light distortions are calculated each frame in the shader. He hit the compile button and uploaded his game. "I am brilliant!" he would think as he stroke his neckbeard as he went to sleep. Now the game uses ftl to get around places fast and it would take an entire of year with the normal engines at 100% to for a player to even notice any differences; the game wasn't designed around relativistic effects. He woke up the next day and checked out his game's forums. "Sweet! Newtonian physics!" someone posted. "NO! It Uses Relativity you fool!" typed the programmer. However, due to how players heuristically understand a game, it became an epademic of "NO YOU FOOOLS!" posts as the programmer tugged on his neckbeard in frusturation and resorted to eating his toe jam as a source of nutrition in keeping up with the forum posts.
(On the other side - the old Microsoft space shooter Allegiance didn't use classical physics -- but the wing-commander style airplane in space flight style. What they added was that the velocity vector would shift much slower so there would be sliding/drifting as part of regular combat. Many players thought there was classical physics being modeled just because the ships slid on turns)
Now in this specific example newtonian physics is an excellent almost 1:1 approximation -- all the features with a much better computational speed.
So I ask again. As a player what do I get with an n-body simulation, or what is different, over patched conics. On one hand, I get L points. On the other hand the physics engine wont be able to simulate as many ships.
Or, to ask another way from a technical standpoint with my very poor understanding of big O notation -- Patched conics is O(x): The physics engine only has to calculate the g force of one planet per ship. N-Body, if one goes for a full simulation of every body in the system, is O(N*x) where N is the number of bodies in a system. Still linear but the slope can be significant -- Saturn has 70 moons. For 128 ships in saturn is 128 gravitational calculations using patched conics. Nbody is 10240 (also adding the effects of the sun and other planets, but not their moons). So what number of ships a physics engine running at 120 fps can model (including all the other elements the physics engine needs to deal with) with patched conics vs nbody in the maxmimum expected size of a system?