serious push for the north american market = stealing talent from wwe who are sick of their position in the company (and don't mind taking a pay cut!) AND stealing writers from wwe who are sick of their ideas being changed 20 minutes before the show starts by a crazy 70 year old man.
ROH can try but they're always going to present a product that looks like shit. TNA can try but they're incompetent. Like you said, New Japan wins half the battle which is more than any other "large" wrestling promotion can say outside of WWE. they just need to figure out that other half of the battle. Storylines that the North American fanbase cares about. How do you do that? Pull a Turner. Steal all the damn WWE talent from Vince. Write stories that actually make sense, and have a payoff. Boom, superior product to WWE. I think if you present a legitimate alternative to WWE, talent will flock over. New Japan has the history and the modern day pedigree to make that happen.
It would be cool if New Japan actually made a push, because like I said, TNA is incompetent and on the verge of death. They were never a serious threat to WWE. ROH has been treading water for years and has always been seen as a feeder league for WWE. New Japan would potentially be legit competition: just look at the shows they throw in Japan, it's like night and day compared to the alternative North American federations, and comes pretty damn close to WWE at capturing that "BIG FIGHT FEEL" at their bigger shows.
I think even WWE senses this, which is why they're trying to work with New Japan at the moment.