Sam Black wrote an article today discussing literally exactly what we've been talking about. I can't post the entire article (as it is in the Premium section) but I will post his decklist as (a) it is a Leyline deck and I know many have been interested in trying such a deck and (b)
I was really happy to see his list as it is quite similar to the one I've been playing.
1. We both play a mana package (his is Elf, Elf, Nissa WSTW where ours is Arbor Elf, Utopia Sprawl, Garruk)
2. We both play full sets of
Once Upon a Time and
Burning-Tree Emissary (now incredible with Once Upon a Time).
3. We both play Voracious Hydra, Walking Ballista, and Karn as scalable win-cons
He brings up a LOT of points we've discussed in this thread including:
1. How we are the most explosive deck in the format.
2. Scalable tools are our best options (and how important scalability is in Devotion in particular)
3. How we are harder to deal with when we have a split of creatures/non-creatures (where possible)
I was extremely impressed with his knowledge of the deep understanding of how Devotion works and how best to exploit what we do best (while mitigating the issues with playing Devotion).
I honestly don't know if Leyline is superior (I think Arbor Elf, Utopia Sprawl, and Abundant Growth may be just as strong as Leyline, Llanowar Elf, Noble Heirarch in terms of developing 4-mana by turn 2). Having said this, Once Upon a Time does not hit Utopia Sprawl (where it does hit Hierarch) and Leyline is a Mana-Sink...so there could be something there. I have been happy with the Arbor Elf and Utopia Sprawl Package; but I will absolutely test Leyline.
One thing I had not tested nearly enough it seems is Vivien, Arkbow Ranger. I assumed it was not strong enough initially, but Sam says that it is far stronger in play than in theory. They cost me a pretty penny online (stupid Pioneer!
) but I will try them out as well and report.
It is a really exciting time for Green Devotion! We are returning to Theros, we've received multiple great cards in the last year, and we are getting written about!