Well, the first night with this deck went fairly well. I went 3-1 with it, losing only to a super low curve Jeskai Artifact deck with Ensoul Artifacts and Shrapnel Blasts. The other three were midrange-ish decks, (4-color Abzan, Mardu Dragons, and BW Eldrazi) and for the most part, these felt fair, neither heavily advantaged or disadvantaged.
A few things did come to light, and I'm planning on tweaking it before I go again tonight. The deck can snowball quickly with just a few small spells at the right time. The sources of life-gain allow to race more effectively than the creature count would suggest.
Slip Through Space is a nice idea, but it often sat in my hand for a long while, and the ability for people to respond to it at instant speed was a real detriment.
Basically, every game, I was sideboarding in some number of Dispel and Negate; the amount of removal was much higher than I expected.
While I only faced it one round myself, I saw a lot of people running Dromoka's Command at other tables, so I think I'm going to reduce the number of Myth Realizeds for the time being.
Two Westvale Abbey
Flips was bit greedy, and I found I wasn’t using the triggers as often as I expected, and I was drawing a lot more land than I needed, so for now I’m going to cut one Abbey.
Ruinous Path is often a little slow for me, so I’m cutting one of those from the main.
Finally, to make up for the loss of some removal, evasion, and a threat, I’m trying out 2 Niblis of Frost, which can fill all of those roles to some degree. It may end up being too slow, but I won’t know till I’ve tested it out a bit.
-1 Westvale Abbey
Flip
-2 Slip Through Space
-1 Ruinous Path
-1 Myth Realized
+2 Dispel
+2 Niblis of Frost
Sideboard and lands I'm going to take a look at as well, but I'll have to finish that tonight.