nah Zoncolan Ovaro is worse. You get steep km in Zoncolan too, just not if you start counting kilometers from 0. Forget 17, one 1000m section between 6km and 8km on Zoncolan just misses 20%
You say 6.5km at 13% is tougher than 10k at 12%.
But Zoncolans middle section is 5km at 15.3%. The next km is 13% meaning 6km at 14.9 % compared to Angilirus 6.5km at 13%
I also personally think its worse having the supertough gradients at the beginning and middle.
Because that way the riders go into the "easier" 9% sections of Zoncolan with absolutely no momentum, the steeper sections already having done the damage,
On Angry Lu on the other hand the pack can go quite fast up the relatively flat by comparison first half, letting fireworks only start towards the end of the climb.
Of course Angiliru loses on almost every statistical comparison. It has a lower average gradient - 9.9 vs 11.9. A lower maximum gradient - 23% vs 26.5% and less kilometers in 10%+ gradients - 6 vs 8. Angiliru is longer however by almost 2km and hence has a higher alltitude gain, but only just 1248 vs 1210, and Zoncolan does take place at a higher alltitude