Medli's Level 4 weapon mission is actually on Dragon Roost and from there you spiral towards the center. You can first clear the west half of the map, which goes down pretty nicely, and the you get funneled in the south, leading to Forest Haven. And for this you have to go around the entire map again, only in reverse this time. You can't get there in the beginning, because you need a Hookshot item card, which is found, where the final mission of the Great Sea Map used to be. You now start on the west half of Outset Island and like on the Great Sea Map, the final mission is right next to you, on the east half of Outset. They did revamp the entire course, which I liked. Playing this map after the Master Quest Map felt just right, but the first half you could also start right after the Great Sea Map. I enjoyed the Great Sea Map quite a lot and the Master Wind Waker version stays close to the experience, whiling offering more challenge, but not too much. The Master Wind Waker Map itself is very solid. And I personally hope that they won't increase the level cap with the upcoming DLCs like they did on Wii U, because that's when the Wii U version really started to become tedious and unenjoyable. Of course it will be necessary to spend some time grinding with the characters, but that's a lot more fun, if you have different costumes and their best weapons available. The 3DS version is a lot more enjoyable overall. That's how much of a difference it can make, alongside the rescaled difficulty. On the Wii U I wasn't even finished with the first Adventure Map in the same time frame. So far I have spent about 160 hours with Legends and I have cleared four Adventure Maps in this time. But it's a lot more fun, if you can just rush through the game without the need of grinding. It's funny, how much you can get used to these new comforts and rely on them.
There you couldn't use other characters (without Co-op) and you didn't have any Fairy Magic. That's interesting, because you're essentially just falling back to Wii U conditions. On the other maps you can compensate this with Fairy Magic, but the Master Wind Waker Map has the new "No Fairy Magic" and "No Magic" rules, which can be troublesome, if you're also locked to a weak character. All of my other characters are around Level 40 and this can be too weak for for the tougher missions. Now, on the Master Wind Waker Map I came to the inevitable point, where this backfired. My favorite character Cia even has reached Level 99 during the course of this map and Link is getting close as well. So far I could go through the game without grinding, thanks to fairies and the ability to chose secondary characters. You can't use any magic there, while she's my weakest character and completely underleveled for the part and the game is just not fun, if you're too weak. I cleared pretty much everything, except for Medli's Level 4 weapon mission.