It would be one thing if a Ux deck were the best. That would allow other color combos to shine, as well as not be fed on in the draft. But Blue in FRA, along with the fixing, is able to siphon the best of other colors without really being punished for it.
For starters, almost all Ux combinations can win by themselves. UB, UR being the strongest. (UW in surgery, and UG if it's there, but it's green so it's most likely splashing a third). Couple this with Blue's card advantage, and the strong amount of fixing possible, and this makes Uxy piles increasingly powerful, with little risk involved.
The side effect this has on the other color combinations is pretty glaring, as it's nothing for Ux based decks to splash an off-color bomb, which takes it away from the other lanes in that color.
Some of the strongest, most fun decks are the non-blue, 2 color synergy piles. GW life gain, RB aggro/grind, RW aggro, Gruul... But none of these get a chance to really thrive given Blue's gravity during the draft.
For example, I would honestly take the strongest BR deck over anything in this format. It just has such reach, and imo is the most fun to play. It got me a direct trophy, it got me a contender trophy. But so much has to go right for it to come together, like opening the correct rares, and that's including the fact that a lot of BR's cards are filler in other decks, but important pieces of the puzzle in the BR shells. So when the Uxy decks absorb the best BR colors into their picks, it leaves scraps and filler for the rest.
Which pulls people into blue, in order to do the same.
Anyway that's my rant. I think this is one of the best formats we've had in a while, but I really do think the cracks are starting to show.