Um, last I checked, Celebi was a FAR superior option in Ubers than Shiftry.
Are you joking me?! You're telling Tsurukawa that you will give Celebi, Drapion, and Lanturn a slight mention while Shiftry gets an immediate adding to the list? I'm sensing a little bias here.
I've been leading with a Celebi in ubers under my "damnsnow" account since the advent of the Ubers Ladder on the official server, and I can tell you from personal experience that Thunder Waving Mewtwo / Kyogre / Deoxys-A while they Ice Beam me, Recovering until an FP and then setting up Stealth Rock and then switching to an appropriate sweeper has been phenomenally useful. Not only does Celebi lose its fire weakness with Kyogre, it provides Paralysis and Stealth Rock support as well. How can this only be considered a slight mention?
Drapion I admittedly have minimal experience with, so I'll let the slight slide here. I do hear, however, that that kid Obi, whoever he is, has been using it to some success. Maybe you should ask him his opinion on it.
Lanturn is great because it takes minimal damage from Water and Ice attacks and completely absorbs Electric ones, making it a beautiful Kyogre counter. It's ability to spread parafusion is also very underrated, as it can take a few hits with that great HP.
Shiftry, on the other hand, gets a speed boost in Sun...and uhh, it gets Sucker Punch I guess for some surprise kills. O, Nasty Plot is cool...except for the fact that when Palkia / Dialga / Darkrai / every other uber so much as looks at it, it faints.
I would give at least Celebi and Lanturn serious consideration, find more information out regarding Drapion, and switch your slight consideration to Shiftry.