I'm gonna be honest: my guess right now is that if AA as a series becomes annualized, alternating between standard AA games and DGS, Capcom USA is only going to localize the mainline games. It would still give them a new AA game every two years, keeps the "safe" market of well-known characters/setting, and avoids the snarls of trying to localize/market the very Japan-heavy DGS.
I hope I'm wrong on that, but I wouldn't be surprised.
That's plausible enough to be incredibly depressing. A fan-translation being the only way to play it in English is starting to seem more and more likely...
Though if something like that ends up going ahead, it might be in Nintendo's best interest to work out an agreement for publishing DGS (and any hypothetical sequels) internationally - the popularity of the series is still fairly consistent despite its current treatment.