'Necrons do it better than TSons'
Look, you don't have to specify Necrons, everything
does it better than TSons. Whatever you're referring to. Thousand Sons are absolutely horrendous, we know.
Even with the issue of gravity pulse, it'd be great for them.
Eh, it only affects the Heldrake since FMCs have Move Through Cover and therefore automatically ignore Dangerous Terrain, so I don't think it's a huge issue (it's unlikely to do much at the best of times, and on a Heldrake with it's 5++, even less so).