My vote goes with Merfolk Seastalkers. It got even better with the slower WWK format and picking either Kor Skyfisher or Conqueror's Pledge sends awful signals with 3/4 more white pickables in the pack. A case could also be made for Bladetusk Boar, but I would avoid white entirely.
I guess I seastalkers, mostly because I prefer blue over white but also because the pack in order of power level goes white card, blue card, white, red, white, blue, meaning if you take seastalkers only the person 5 seats away from you gets a blue card from the pack probably.
I'd just take Pledge as it's a legitimate bomb. If the white doesn't open up it can still be safely abandoned, and if it does you've profited massively. Plus, there's even an outside chance that a white card will come back around - especially as Aeronaut requires a commitment to white that other people may not want to make when they see three white cards in the same pack - and if they do they've probably already cut you off in white as it is.
I took Pledge, got a Monument pick 2 or 3 in Pack 2 and lived the dream of T5 Pledge, T6 Monument in my very first game. I also ended up with Strength of the Tajuru and a fairly solid set of WG creatures (River Boa, Skyfisher, Gnarlid Pack, Terastodon (!), etc.) I 3-0ed the draft but it was Swiss so I get no props for that. I just thought the first pick was very interesting. I took Kieran's view that Pledge is a bomb and I could always abandon it if the W didn't flow pack 1 (implying pack 3, too).
I think it's between skyfisher and seastalkers - prob go with the seastakers due to the quantity of other good White cards. What did mr baker take and how did it work out?