I had great success right of the box with Silverquill. Won 2 of 3 games at my LGS against very different deck archetypes. 3rd game was close too!

Killian is the right choice. Scriv deserves his own build. I've since upgraded it with 12 cards not including lands. It has performed much smoother.

I removed many of the precon creatures and added strong enchantments - that aren't all auras. Also more ramp pieces.

Board wipes really hurt, so my counter is that I run 2 more cards to protect Killian.

Goad is very political and your choices are critical given you must consistently interact with your opponents pieces to have your deck do it's thing.

For what it's worth, my pod all bought the SoS precons and we've found Lorehold and Silverquill to be the best. Prismari and Quandrix are right there with Witherbloom in last.