Well, isn't that the thing right there? LJN is a shitty developer. Capcom and Konami are not. So perhaps it's not really a case of Japanese versus American developers, but the caliber of developer that the license goes to.
Also I didn't realize this was an NES topic. Re-reading the OP does seem NES focused but I didn't pick up on that at first. I think if you look beyond the NES, you see better Western-developed licensed games. Cool Spot was a much better game than Spot for NES.
Of course this is subjective and very hard to quantify. But I think it's easy to have a better impression at first, because the games we tend to hear about here are usually the good ones. If you start poking around random Japanese releases, you find a lot of shit. There's a Lupin III game for the Saturn that literally has no gameplay, just information about the show and a few video clips. It's hard to imagine that type of thing getting the green light for an American cartoon.