UW/UWR is easily one of the best decks in the format, as with Storm, and it made no showing at the top. Modern is like Legacy, but if everyone played the metagame at the same time. It changes incredibly fast for a format with no rotation, and is INCREDIBLY skill intensive. It is often harder to play than Legacy. If you make a mistake you cannot recover. Your opponents' cards and interactions are powerful enough to crush you, but your individual cards and card selection is/are bad on their own.

Synergy is HUGE in Modern, whereas in Legacy synergy is a side effect of the most powerful Spells being played together. This is especially true with Storm. You can kill people with like 3 cards in Legacy. In Modern you a) need to hit 20 - not 10 copies of your kill, and b) have almost zero good draw Spells outside of Manamorphose, which is only good with an active permanent. Every Spell in Legacy Storm is basically broken in Modern, short of the Tutor interaction, and Ad Nauseum being unplayable.

Birting Pod takes the place of Elves. It plays an aggressive midrange strategy, whereas Elves plays straight aggro, and has a combo kill. It plays a pseudo toolbox strategy in Pod and Chord, replacing Zenith and Order. You can then combo kill people around a turn slower than most combo decks. Your combo is more consistent because of that, but being Creature-based is also easier to interact with. The main difference here is that your games are less about explosive T1 and T2 plays in Modern, allowing the deck a small set-up time that you don't get in Elves. There's also additional interaction in Modern as people don't just go "Doesn't matter; have Force" and actually play a lot of cards to mess with plans.

One thing that was said on Stream was that this additional interaction causes bigger, fatter combos to be more relevant, hence why Kiki-Jiki is played on Modern, but also creates these odd situations where someone tries to win and are stopped. The second player tries to win and is stopped, and then you have a lone Inkmoth Nexus trying beat a Snapcaster Mage in what is essentially a race to the finish now that everyone has been crippled. It's then about making the most with very little.

So basically the opening turns are like a game of chicken, then T3-5 is like Legacy, then it's like Limited.

EDIT: I agree with the previously mentioned Planeswalker test. *Sleeves up Tamiyo and Gideon*