I'm pretty sure that Orks and perhaps to a lesser extent nids will be made marginally more survivable when they get thir 6th edition 'dex as recompense for overwatch. I'm pretty sure orks will get universal 6+ fnp which should help a bit.
Its basically about giving them methods to get into combat before they're shot to pieces. This is why everyone cries bitter tears over Banshees, there's just no way to assault something without opening yourself up to a round of shooting and since they're somewhat fragile all it takes is a solid round of bolter fire to kick their teeth out. Of course this could largely be considered a matter of target priority and movement, and of course there are many ways around it but that's what people will fixate on, "I can't use this scalpel like a baseball bat, how will I hit home runs now?"
Orks are a baseball bat though, and as such there should ideally be precious little artistry to their usage. Run at the things that aren't green enough and krump some 'eds. They're all ready quite amazing at this as is mind you. Moderately high toughness, obscenely cheap, hit like a ton of green bricks if they make it, and fearless into the bargain until they're well under useful size anyways. They wear wife beaters for armor of course, but for 6 points a pop your defense is really body count not armor.
A 6+ fnp will give them that little edge they need to be better bulldozers in my opinion. Some niftier options would be rather swanky as well. Maybe different weapon options for nobz, different AP values on their h2h weapons (ap5 would be really nifty I think, maybe ap4 on the charge for choppas, might constitute a points increase though which would be less than favorable, especially when dealing with MEQ and TEQ.)
Not really sure why 'Ard Boyz are a 0-1 choice either, should just be an option. Maybe a new(old) unit like madboyz would be interesting. No ranged attacks and maybe rage to go along with their furious charge, or perhaps a more nuanced interaction with weirdboyz. Just spitballing really.
What premier assault armies need is either A. slightly greater survivability to compensate for overwatch or B. better deployment and movement options. Orks all ready have fast assault vehicles (they're made out of toilet paper though.) and not so fast assault vehicles that are made out of two-ply extra strong Charmin. Some more deep striking options for elite assault units is really all I'd want on that front. (tellyportin' meganobz thanxbai.)