Nintendo releasing DLC means very little. So far what I've seen is that the DLC isn't really necessary at all to beat the game or to understand it better. Also, the 3DS has more than Mario. It has some other 1st party titles, and some 3rd party titles that look quite good as well. There aren't just games that are "coming out soon" or whatever. We have a nice Resident Evil game, a revived Kid Icarus title, Tales of the Abyss port (that many people didn't or couldn't get their hands on for the original), some well-made remakes/upgraded ports, there's a kingdom hearts game, theatrhythm final fantasy, and a good handful more. There's just as much that's about to come out as well scheduled for release within the next year.
Also, to understand region-lock, you have to understand that it is done for a reason. Region-locking is mostly done for anti-piracy and child protection/parental locks.
