It is lackluster imo. What's there is good, but we needed way more. Most of the time when you're playing the only things that you're constantly hearing are your footsteps, ambient noise and some piano keys here and there (Which get rather annoying since it's always the same ones - there's not enough variety). There's also the fact that BotW has voice acting and it got in the way of the OST during cutscenes imo, since in older games I could read the story at my own pace and hear the background music while doing it.
I really don't get the "but if the overworld had music it'd get repetitive" comments that people make when talking about this game's OST tbh, because Nintendo could've easily made music work with the overworld, they just had to make longer themes that also changed on the fly based on the environment/time of day/enemies/etc (Basically what happens in games like Mario and Banjo-Kazooie when going underwater, but more involved).
EDIT: I'm also mad that they didn't make a proper staff roll theme and instead reused music from various other parts of the game, it felt cheap even if the music was good.
