@ Tao, I agree with your observations. I've been dumping my hand out by turn 4. I spew everything out and usually the win/loss is decided by then. Against quick decks like zoo/folk/goblins, my build is excellent because I get all my stuff out quickly and start bashing. Iona is also GG when it lands and the gas problem disappears because they can't cast anything.
Against the rock etc, I split the games because sometimes I "explode" too quickly and just kick their ass with Iona. In other games, they throw Thoughtseize, Hymm, Vindicates at me and it comes down to a grinding game which I usually lose.
I tried incorporating Vengevine/NO in my vial lists and observed the same things you did. If I cut Noble for either, it's awkward because I can't cast NO with vial and Vial @ 4 is very slow. What I ideally wanted was to replace Noble with a creature based bomb like Dark Confidant which can be vialed out. I however find that the splash is bad for my manabase and I could not run Horizon Canopies, which are excellent in this deck. I have therefore settled on the mighty Sylvan Library as a 2 of, replacing 2 Nobles. Here is the current list:
4 Vial
4 GSZ
4 STP
2 Sylvan Library
4 Mother of Runes
2 Noble Heirarch
4 Goyf
4 KOTR
4 Fauna
3 Pridemage
1 Teeq
1 Iona
1 Loyal Retainers
4 Heath
2 Strand (Mind games indicating Bant- Leading Strand -> Savanna, might cause players to think Bant, giving me time to Teeq them out)
2 Misty (Ditto)
3 Savanna
3 Canopy (So good, I upped to 3)
1 Plains
1 Forest
1 Karakas
1 Arbor
4 Wasteland
I realized in my previous build, I had too many turn 1 plays: 4 Mom, 4 Vial, 4 Noble, 4 GSZ- Sometimes I can't decide which to play first and I love this. To cut some stuff for Gas, the most obvious slots to trim are the 1 drops and the worse of them is Noble since I don't run NO. I trimmed 2 for Sylvan Library which is an excellent bomb that gels well with my curve. I still have 24! (25 if you count arbor) Creatures, which is plenty for Fauna, so that's not an issue. I have another testing session tonight so I will update on results.
@ My board looks like this now:
2 Path (Or more chokes if I expect more blue)
1 Maze of Ith
4 Enlightened Tutor
1 Jitte
1 Null Rod
1 Ethersworn Cannonist
1 Tormod's Crypt
1 Needle (Or Revoker since revoker hits combo)
1 Oblivion Ring (Emrakul/Tutorable anti enchantment)
1 Choke
1 Faerie Macabre (Good to draw in opening 7 vs Dredge/Reanimator and also tutorable with Fauna, Loaming Shaman is too slow)
This SB has been good. Post board I have a lot of outs against ANT/TES. I bring in: 4 Tutor, 1 Null Rod, 1 Cannonist, 1 Revoker (If I run it). This gives me a 8 T2 hate (including Gaddock in the main) and an additional 8 T3 (4 Fauna, 4 GSZ). Giving me 16 live cards against combo. I think that's a pretty safe number. Being varied also means you don't lose to Echoing Truth. :)

