Two games today:
G1: vs Ezuri, Claw of Progress and Omnath, Locus of Rage. Win.
G2: vs Ezuri, Claw of Progress and Sidisi, Brood Tyrant. Loss.

Not really sure if I like the new mulligan.

Three games yesterday:
G1: vs Ghave, Guru of Spores and Nath of the Gilt-Leaf(elfball).
Nath flooded the board and steamrolled us. Loss.

G2: vs Ghave, Guru of Spores, Nath of the Gilt-Leaf, Ezuri, Claw of Progress and Tajic, Blade of the Legion.
I dominated with Avenger of Zendikar and Lavinia of the Tenth. Win.

G3: vs Ghave, Guru of Spores, Nath of the Gilt-Leaf, Ezuri, Claw of Progress and Zurgo Helmsmasher.
Incredible start with T1 Exploration, T2 Rhystic Study, T3 Mystic Remora + Sakura-Tribe Elder. Became too much of a target, and with 4-vs-1 I was soon eliminated. Loss.

Indigoindigo - how often do you find yourself playing Ixidron when you have it in hand? While it is a great card, I see it hurting, rather than helping, a Roon deck - unless there is something I am missing...if so, please explain - I am always looking for ways to improve my own deck, Roon Re-Imagined.

Ixidron is for when I'm way behind or there's a big threat (or several) that can't be dealed with by conventional sweepers / spot removal. Losing my creatures aren't that bad, as the deck often builds value by ETB-triggers, not board state. It also has synergy with Roon of the Hidden Realm or Brago, King Eternal if I can cast them next turn, flipping 1 or more of my creatures each turn.

It's not the best card in the deck, but occationally useful.

Indigoindigo - thank you for explaining your rationale behind Ixidron.