I've made several improvements to this in 1.6:

• For some reason, the A* code has trouble finding a path into the arena but much less trouble coming out of the arena (we time-out). I've fixed this by trying a reverse path if we exceed our iteration limit.
• The AI always uses a nav path, even if there are no anchor objects near by. This is possible now that we can have private nav paths on ships (which the ships free when they're done).
• When following a nav path, if we hit a wall, we backtrack a little bit and then try again. This helps us navigate in cases where the ship deviates slightly from the nav path.
• The avoid potential vector is more accurate now. Once a ship hits a wall, we set the avoid vector based on the actual geometries of the wall (using point-in-object tests) instead of based on the wall center.

There are still many cases which we don't handle. If we're navigating without nav paths (e.g., orbiting) then we don't deal with walls. We can fix this later by changing our behavior when we hit a wall (or by using nav paths in more cases).