A bit of commentary on Native/Aberrant functions:
The reason why I chose to add this mechanic wasn't to add some new element to the game. In fact I added it to simplify and group several similar mechanics, eliminating the need for 'situational' and explanatory text for each. The main instances were racial special rules, see here:
Demiurg and Tyranids have a special rule for LD tests when navigating Celestial Phenomena.
Eldar have a rule for Ramming, and one for Warp Rifts.
Orks have a rule for All Ahead Full.
Dark Eldar have a rule for Come to New Heading.
Other than that, there was a rule for escort squadrons and Celestial Phenomena (which we changed to a type bonus).
To simplify all these rules, I use the Native/Aberrant mechanic, forcing them to all work the same. There is further benefit from this rule as well, particularly for slow fleets, and to squadroning Capital Ships (most don't like to).
Orks: Native (All Ahead Full, Come to New Heading, Ram, Asteroid Fields)
There are a few reasons for this, mainly the loss of 'auto-pass All Ahead Full' orders, but also their 'slow to turn' nature and weak side weapons. Also, Orks are a pirate fleet (in most circumstance), but most players fear going through Asteroid Fields due to poor leadership and few shields. Generally, you could assume that Orks would be fans of crazy maneuvers at high speeds.
Eldar: Native (Asteroid Fields) Aberrant (Warp Rifts, Ram)
CWE: Abberant (Warp Rifts, Ram)
Dark Eldar: Native (CTNH, AAF, Asteroid Fields), Aberrant (Warp Rifts, Ram)
Demiurg: Native (Disengage, Asteroid Fields, Warp Rifts)
Necrons: Native (Disengage)
Tyranids: Native (Asteroid Fields, Warp Rifts)