I think you're forgetting that Pidgeot is FRAIL. While its stats suggest that it takes hits similar to Staraptor, the lack of Intimidate just says "why the hell did I give this Defense EVs?".Of you could stay in because Thunderbolt and Ice Beam don't own Pidgeot like they do Staraptor (After Roost or no). If you're just using Intimdate + U-Turn, you might as well forget the bulky set and just use CB Raptor since it scouts and does decent damage. People underestimate Pidgeot and forget it can break 300 speed, so they usually end up keeping things in to be Featherdanced. Once they realize they can't take out Pidgeot they switch, and that is when you predict and nail the new switchin with Featherdance.
I mean, the premise of this set seems to be to switch in to powerful physical attacks and then Featherdance and U-Turn out. Thats all well and good, but if your opponent switchens in a special attacking pokemon or a mixed pokemon with special attacks, Staraptor is still SOL. 50 SDef is quite awful. I've been using the Pidgeot set in UU and Lucario Aura Sphere did 52% to Pidgeot. Staraptor would always be 2HKO'd. Naturally you can't roost on Aura Sphere in that case, but Air Slash took out over half of Lucario's HP so it did fine. Air Slash helps Pidgeot quite a bit more than Aerial Ace/Brave Bird since it isn't affected by opposing Intimidates and it has more power than AA and no recoil like Brave Bird.
Noctowl can also do these things and has more special durability, but its physical defense is awful.
Now I made the Pidgeot set for UU based on these to be sure, since it says Hello to starting fighters, but it still has quite a bit of merit since it is special based and the Steel walss in UU don't stop it, and really hate Featherdance.
Not convinced? Here, let's run some calculations.
Choice Scarf Heracross's Stone Edge on Staraptor:
173 HP - 204 HP (50.28% - 58.28%)
Staraptor has a shot at surviving, but let's look at Pidgeot.
Against max/max Pidgeot:
203 HP - 239 HP (54.86% - 64.69%)
Notice the difference? Wait a minute... I just helped prove yourself...
Also, you mentioned that Pidgeot can use HP Fighting for Rock- and Steel-types, but how is it going to find room for that in a moveset consisting of Roost / U-Turn / Air Slash / Featherdance?