It always happens in the early days of a new expansion. Players are unfamiliar with the cards, and what cards work best together. Also, they have had little time to practise, often operating on theory alone. These clashing theories combine with Rochester drafting the same set three times can lead to some pretty shocking results.
A number of people read their table like a book, sliding into ignored colors to reap incredible rewards, such as:
3 Repel with 3 Scrivner to get them back
3 Repel, 2 Syncopate, 2 Aether Burst
3 Cephalid Looters (but woefully few Threshold cards)
4 Mystic Zealot
3 Aven Flock, 2 Aven Cloudchaser, 2 Hallowed Healer
3 Hallowed Healer, 2 Puppeteer
4 Simplify (in the sideboard, just in case)
3 Muscle Burst, 2 Diligent Farmhand
3 Firebolt and a Pardic Firecat
4 Second Thoughts (and a fifth in reserve!)
2 Morbid Hunger, 2 Patriarch's Desire, 3 Chainflinger
But bear in mind, those are just the aberrants.
Here at Sideboard.com, our Scientists have been dreadfully busy using their skills to actualize the songs of Thomas Dolby, and so there's been precious little science left over for the rest of us. We've scraped together the dregs for a quick statistical analysis. Hopefully it will satisfy.
As expected, Rochester draft is self-correcting. Colors were pretty evenly played across the board, with only black coming up short. Blue-white was far and away the most popular combination, offering common bounce spells, no-nonsense removal in Second Thoughts, and fliers a-go-go. Next in line are the green beatdown decks, taking advantage of an incredible creature line to catch slower decks unawares.
COLOR COMBINATION BREAKDOWN
Three-Color Decks: 23