Focus Blast is an AWFUL move in Ubers, since if you miss....you die, since most users of FBlast are quite "frail."
And Scarchomp is quite vicious, because that extra 2 base speed really makes him so good at tearing stuff up with that Outrage. Palkia wishes it had 102 base speed.
Focus Blast isn't awful. It provides great coverage alongside Dark Pulse with Darkrai, and perhaps most importantly, it can OHKO opposing Darkrai.
By your logical, I could argue that Hypnosis is AWFUL. Look how common Gengar was in OU before it got nerfed from 70% to 60%. If it missed, Gengar was dead thanks to paper defences. Focus Blast has the exact same accuracy, with a very high base power, great offensive typing, usually providing great coverage alongside other moves, and it has a 30% chance of lowering SDef.
However, Aura Sphere > Focus Blast in most scenarios. The only exception is on Scarf Mewtwo, when Focus Blast is needed to OHKO Darkrai, where as Aura Sphere ony has a 15.38% chance. There is no way I'm using Aura Sphere when I have the ability to outspeed and OHKO such a prominent threat. And in case of a miss, Darkrai will never OHKO; worse case scenario is Dark Void, and that move only hits 10% more often than Focus Blast.
I have been using Wobbuffet and Giratina-O together, and it brutaly slaughters almost every stall team I have faced. Basicly, Wobbuffet encores something like Lugia, and sets up Giratina-O for a sweep. This works because stall teams don't have much of an answer for Giratina-O except Latias.
If Giratina has Outrage, Latias won't want to swap into it. Use the mixed attacker set, as that works best against the majority of stall teams - Draco Meteor for Groudon and Giratina, Thunder for Lugia and Forretress, Outrage for Latias and Blissey.