After some experimentation, I can confirm that the pool was, indeed, quite strong. Broken comes to mind. But not Grixis. This is what I played in week three:
Fast on the board, attacking for three in the air on turn three virtually every game, three pieces of unconditional removal, card advantage engine in Bishop, race winner in Tenacity, a bomb rare in Plate. This deck, and its week two incarnation (no Tenacity) did not lose a match. Should have lost one, but the opponent let their
Elusive Tormentor die in combat, which allowed me to come back from very far behind.
And this is what I did not play:
This blue pool has everything: tons of card advantage with Jace and Investigation, removal with two
Sleep Paralysis, tempo tools with Mangler and Scrutiny. But it does not block well. I played it week one, had a lot of fun, went 2-1. Then Spike started whispering of white, I lost game one of match four with UB, sideboarded into BW, and that was that for blue.
I finished the league at 8-1. Cashed in my winnings for some boosters, opened another pool. Looks like a nice GW aggro curve, possibly splashing for Arlinn Korr. Not sure the splash is worth it, but I'm playing these for fun, right? Shut up, Spike!