Maybe Nintendo has given up on Tri Force Heroes, but I haven't and I'm still giving potential DLC some thoughts. If you didn't know this already, data miners had found out about six DLC costumes and two additional DLC areas after the game's release, as documented on The Cutting Room Floor. We got one of the areas and two of the costumes with the first update, but we never saw the rest.
Originally I thought that the rest of the DLC might be some 30th Anniversary celebratory content, which might have gotten cancelled together with any other 30th Anniversary plans, when they delayed Breath of the Wild. But there's another possibility. What if they have planned to add some promotional content for Breath of the Wild?
- Outfits based on Link's gear in the game.
- A Sheikah Shrine area.
- Additional Lucky Lobby Ball Song with the game's theme.
They could dive a little bit in the technology stuff here already, where Sheikah Shrine trials would fit the level based structure of Tri Force Heroes quite well. Instead of the typical Triforce portal at the end of each floor, they could have the three Links gather around a Sheikah Eye. This would be more puzzle based, after the Den of Trials was entirely combat-based. But one of the Guardians could even become the boss of the area.
The new outfits could feature Link's blue tunic from the game and maybe also some other gear from the game, like the Chain Mail. Or there could be outfits based on new enemies, like some Bokoblin outfit. But one or two outfits from the game probably would be enough, because there are still lots of potential outfits based on classic Zelda left, e.g. the Fairy Costume. This could also be mixed, for example having a costume based on the Old Man, who's both from classic Zelda games, as well as Breath of the Wild. Or as a reward for the Sheikah trial you could get a Sheik costume.
Now, for example the blue Breath of the Wild tunic could upgrade the Bow with Fire Arrows or some new arrow type. Fire Arrows certainly would be helpful throughout the game without completely breaking it.
If such a DLC really will happen, it does make sense that they haven't released it yet, because they have to show us more of the new game first, before such a content pack could be appreciated. I still could see something like a Zelda Direct happening later this year, where they talk more about Breath of the Wild, but also show us upcoming DLCs for both Tri Force Heroes and Hyrule Warriors: Legends (the latter could also get some Breath of the Wild costume for Link).
Of course it's more likely that I'm beating a dead horse here and Tri Force Heroes is simply done. But I'm just entertaining thoughts.