Super Mario Maker 3DS is a great port of an excellent Wii U game that brings most of the home console game's features to the small handheld. Given the large audience the 3DS has over Nintendo's failed tablet controller console, it should mean more people get to play it. Sadly, though, it's missing one pretty important feature: online level sharing. Nintendo has often pushed location-based content sharing through StreetPass, but here it feels like a real step back for the Mario Maker franchise.
There is an argument to be made that the 3DS version of Mario Maker didn't need online level sharing. It includes 100 Nintendo-made levels that present a beefy challenge, plus a constantly changing list of 100 levels made by owners of the Wii U game, essentially meaning you're not going to suffer from a lack of content. But, and this is a rather large but, that argument is wrong. It just feels like a real shame that anything brilliant made on the 3DS version of the game can only be spread by local wireless sharing or StreetPassing.
In a somewhat neat touch, you can share in-progress levels with friends who can then collaborate with you on designs - a feature I expect will be very useful amongst friendship groups. And there is something to be said for the joy of discovering new levels that have been automatically downloaded on your morning commute thanks to StreetPass. Sadly I think for a lot of players that will be a joy that isn't experienced very often, if at all.
I'm someone who will dabble with level creation (more so in Mario Maker than in titles like LittleBigPlanet) but I get most out of the game by playing the included levels. As I don't hang out with anyone who owns a 3DS and my StreetPass success rate is about one in every 100 commutes, I'm rarely going to play any levels created on the handheld. And it works the other way too: players who get a kick out of making levels may find that they aren't able to get them played by many people.
There's little else to say about the issue really. Super Mario Maker makes level creation something that everyone can have a stab at, with the barrier to entry far lower than in other titles that offer similar functionality. Considering the creation side of the package has been handled so excellently, it's a little confusing why sharing has been hamstrung by cute but woefully inadequate social functionality.