I looked at the laps in Planica and they look good. The individual start races are interesting. 2 different laps, the women will do 1 on the first and 1 on the second, the men an additional one on the 2nd. So at least for the women's race nobody will benefit from skiing behind anyone and even in the men's race it's gonna be hard for the favourites to get lucky.
The 7.15km lap for the 50km race also looks hard, really long uphill sections, but never absurdly steep. Looks perfect for Iivo (knocks on wood).
Edit:
1,088m of altitude gain for the men's skiathlon (half of it for the women), 1,869m for the 50km men's race, 590m for the 15km race, 385m for the 10km race and 1,088m for the 30km women's race. Even the sprint course features 49m of altitude gain and a longer climb with am altitude gain of 32m, they all look hard.