The challenges associated with designing intuitive editing tools for Zelda are far greater, I think, than in the case of Mario Brothers. For one thing Zelda is potentially much more complicated in terms of layout. As for eras of play, I think the top-down 2D perspective titles are the most feasible. Specifically, the original NES Legend of Zelda, SNES Link to the Past, Link Between Worlds on the 3DS and maybe one more (I'm not sure which). Maps could consist of a bunch of interconnected rooms or outdoor zones that can be filled in with monsters, chests, claypots, traps and other obstacles/challenges. Treasure should probably be limited to classic items such as the lantern, raft, ladder, bow, boomerang, wands, outfits, as well as shield and sword upgrades. Consumables can be hearts, arrows, rupees, and bombs. I'm not exactly sure what the best approach would be for bosses other than the obvious solution of having some customizable templates, such as a dragon that can be designated with a specific weakness or one of several different breath weapons.
The way levels are shared through the Nintendo network would require a bit of tweaking. Perhaps the best way to handle it would be a generic central hub area that branches off into user created overland zones with entrances to dungeons (each of which contains a shard of the Triforce). Merchants should also be included in some way, shape, or form, although I'm not sure whether or not it's best to let their location and wares be defined by the level creators.
Other than that, I can't think of any particular aspects of a hypothetical "Zelda Maker" that would have to be radically different than the format set by Mario Maker. Not being a developer, I'm sure there's some important things I am oblivious to, but if Nintendo can pull the concept off elegantly then I have no doubt it would be a welcome addition to the franchise. I've always wanted to craft my own Zelda dungeons and I'm sure there are more than a few fans out there who feel likewise.