Well, those are the outfits that Link, Mipha, Urbosa, Daruk and Rivali used in BotW cutscenes. They are the champions' attires, they are lore related... so, even if it's convenient and "cheap" from the development side of things, it still makes sense... I don't mind it at all.
In terms of enemies, yes, I wish we'd see different and new ones, but that's something I think even of BotW... maybe we'll see some different ones or at least variations (as we've seen the Hyrulean soldiers), but who knows...