Well, I'll go over them one by one.
Crimson Hellkite vs. Two-Headed Dragon - This one is easy. Crimson Hellkite falls squarely into the Pretty Much Uncastable category; it'd lose to almost anything.
Nekrataal vs. Dark Hatchling - I always love Nekrataal. It's cheaper, and the 2/1 first striking body means it's not nearly as hard to deal with as the 2/2 flyer. In it goes.
Noble Purpose vs. Orim's Prayer - I don't see either of them going into a Constructed deck, so I looked at Limited. Orim's Prayer provides a small, but decent effect for an affordable price...but Noble Purpose is an I Win card. I play Noble Purpose, take a few swings with my army, and any chance you had of winning is gone. I voted Prayer.
Let's see, what else...the stupid Wizards' site just puked, so let's see what I can remember.
Worship vs. Pariah vs. Kismet - Kismet was only ever played in Stasis decks, and it's *boring* in draft/sealed. Pariah is neat, but I'd MUCH rather open Worship in a pack...it also makes for more interesting interaction, as the Worship player has to protect his army.
Birds & Wall vs. Tree & Elves - Birds are out of flavor for green. They fly, and green doesn't. Birds should have been white. Vine Trellis is good. Very good. Possibly too good. Whereas Tree is readily available to anyone who's in Standard now, and Elves...I mean, they're ELVES. Without the Lawnmowers, playing Elvish Champion just feels empty somehow. I voted Tree & Elves.
I'll look at the rest later.