It's definitely not a 30 seconds increase though, more like 10 - 20 seconds, maybe.
Out of curiosity, I checked from YouTube, previous time was near 15s, and current near 30s, so it's more a 15s time added than 10s. Definitely not 30s, which would be the entire load time.
Anyway, it's weird. I wonder if there's an explanation or it's just a bug.
I love the new map, I mean the overworld. It really feels like a Zelda game where you have to plan which object you'll grab first to unlock the quickest route. The menace of the map resetting does remind the mechanics and atmosphere of Majora's Mask, and so does the map layout with the Deku area in the South, the Zora area in the West, etc. It seems easy to solve in a first run, though, without ever resetting the map.
Young Link is as fun as real form Midna to play with, really powerful. A shame there isn't missions tailored for him (like there wasn't for Midna), is it because the characters can be bought separately from the levels (no clue if they are, I got the season pass)? But this time more missions can be played with any character, so it's OK.
@Nohar: oh I agree it's annoying, never said it wasn't, but it's still just 15s. Compared with the length of the missions (10-15mn) and the retry option for especially difficult levels, I'm surprised by the posts that present the added time as game breaking or unbearable. It's really a minor nuisance IMO, that's all I'm saying, I wanted to put it into perspective so people who don't have access to the patch yet don't get the wrong idea. But yeah, psychologically it's frustrating, especially since it doesn't seem justified, and I hope it'll get corrected too (maybe by the next update, the Ganon/Boss pack), along with the mislabel in some new missions.