Yeah, I'm thinking they're going to have to give us some way to share patterns, besides adding them from the creator's town. QR codes were probably one of the best features they added to NL, and I can't imagine Nintendo doesn't know how popular they were - look at the Pinterest boards and Tumblr blogs dedicated entirely to curating QR codes.
I think a catalog and codes would be cool, I'm just wondering how they'll do that with patterns. The thing with dream towns in ACNL and display rooms in HHD was that it takes a lot more effort to perfect them than it does to create one pattern, and the display rooms also get taken down after a while IIRC. It would suck to lose your favorite patterns because the creator is no longer active.
Hopefully they also won't add strict limitations if they go another route, either. If they switched to sharing patterns only through dream towns, for instance, it would be cool if they added a "dream boutique", like how Wendell would share your designs, but allow you to choose which to share and not limit you in sharing them. For instance, if it were basically the size of the Able Sisters' shop, I think that would be disappointing in how much it would limit really active creators in sharing their patterns.
As for what we can actually add patterns to, since that was the original point of the thread, I don't really think we'll get more options than before, if even that. Instead, I'm hoping they'll add even more options. Looking at the new clothing, I'm wondering how much we'll be able to do with that - will we only be able to make plain t-shirts, or will we also get to choose add-ons, like collars, capes and bows? Will it cost extra? Will designing paths still be a thing, and if so, will they also be more textured? Will we get to choose sounds (which is what I really want, TBH) - so if you make a brick path, it'll sound like walking on pavement, or if you make a grassy path, it'll sound like walking on grass?
Otherwise, I don't need or want to put textures on everything. Just give me more options to customize patterns, if anything, and I'm set.