Yeah, the fixing is going to be far less plentiful with only one pack of Fate. Which is going to make trying to play a full three colors somewhere between difficult and painful. However I think there are definitely things that would push me to splash a color for a card or two, especially if I have a couple Evolving Wilds.
For Sealed, I feel like the 3 mana dragon "rocks" might be playable. Far better than the banners that were mediocre.
Based on past "theme" packs, I'd expect one of them in every prerelease pack almost. Slow fixing but will make second color easier. Third could be hard to hit but there a number of bombs worth it.
Base 2, 3 depending on what you open. Any more is too hard on mana. This isn't Khans where you can take all the lands and play 5 color anymore. Lands and fixing don't seem as abundant as they were in formats like Dragon's Maze so you should probably just pick a clan and stick with it.
Dunes of Zairo
SHANDALAR
Innistrad - The Darkest Night
~THE RAVNICAN CONSORTIUM~
A Community Set
Commander: Allies & Adversaries
EDH DECKS
[to be updated
OTHER DECKS
UR Blue-Red Control
Modern:
UBR Grixis Control
UWR Jeskai Control
Based on past "theme" packs, I'd expect one of them in every prerelease pack almost. Slow fixing but will make second color easier. Third could be hard to hit but there a number of bombs worth it.