Yeah, me too. :/ I'm really upset, too, because those features are ones I really loved in ORAS. I mean, the whole concept of being able to actually physically fly around over the region is just really cool, but the fact that it eventually allows you to fly without needing a Pokemon to have the move is so useful. And DexNav makes catching Pokemon a lot more interesting, particularly as somebody who's been too lazy to bother with breeding Egg Moves except once. I feel like DexNav has a slight potential for return, at least in some capacity, but soaring is probably dead.
I honestly don't understand why Game Freak consistently does stuff like that, though. I guess the bright side is that it gives different games different positives even if they're outdated in other ways, like gen 2 (and its remakes) allowing you to travel in multiple regions, HGSS having the Pokemon following you, Emerald having the most fleshed-out Battle Frontier stuff, but as a rule games tend to accumulate more features, not toss away fan favorites for no reason. There's even stuff like battle start animations that were introduced in Crystal and then disappeared until Emerald. The only logic I can see for it is that removing features like that will make them a shiny incentive to buy a game if/when they bring them back.