First bans:
Na'Vi: Bane and Invoker
Both of these heroes are unorthodox picks/bans (at least right now)and are weird to be included in the first banning phase - considering that this is Na'Vi. The Invoker ban from sigma would have made sense as Dendi was able to use Invoker very well in game 1 of the series, but for Na'Vi to ban it was probably more of a statement rather than a strategical move. Banning Bane however was most likely to create space for XBOCT's Lifestealer.
Sigma.Int: Enchantress and Io
Enchantress ban is fairly standard against a team with a #4 position player that is exceptionally good at micro. The Io ban here suggests something about their strategy - they most likely would have a team composition that would be very weak against Io ganks.
First picks:
Na'Vi: Timbersaw and Crystal Maiden
Both of these heroes are tier 1 picks, and are very flexible in terms of laning - Crystal Maiden can roam, babysit and/or jungle, while Timbersaw is a solid pick for mid, solo hard or safe lane. Nothing too special here, but it should be noted that these heroes are very standard and safe picks that do not allow the opponents to read your strategy.
Sigma.Int: Alchemist and Visage
The first picks for Sigma are similar to those of Na'Vi, safe and flexible picks that don't reveal your macro strategy. Sigma decided to secure their two support picks here to ensure that they have a powerful tri-lane that gives way for kills.
Second Bans:
Na'Vi: Nature's Prophet and Razor
Na'Vi doesn't like playing against split push, so the Nature's Prophet ban here is understandable. The Razor ban here is very interesting though. The Razor ban serves two roles - removing one potential counter to the Lifestealer if it gets through, and setting up a safe Outworld Devourer pick.
Sigma.Int: Chen and Lifestealer
Both are respect bans and bans for heroes that did well for the previous game - these two are two heroes that Na'Vi plays exceptionally well and were very dangerous, so bans were to be expected.
Second picks:
Na'Vi: Pugna and Outworld Devourer
This is the part that made me want to write this analysis. Right after the Razor ban, Na'vi immediately picked Pugna. The ban suggested an Outworld Devourer pick, but since Sigma was out of bans, they had to pick him to deny it from Na'Vi. But since Na'Vi has a Pugna, an Outworld Devourer pick would be very risky. Sigma decided to go for a safer route and not choose outworld devourer, which allowed Na'Vi to pick him in this phase.
Sigma.Int: Clockwerk and Nyx Assassin
The Clockwerk pick here was most likely to get a hero with a gap closer for easier ganks. The Nyx Assassin pick was the remaining option to counter Outworld Devourer in one way or another.
Last bans:
Na'Vi: Mirana
Not very sure why they banned out Mirana here. Possibly because of Sigma having a gank heavy lineup up to this point, and Mirana could make a reasonable #1 position carry.
Sigma.Int: Dazzle
The Dazzle ban here was most likely because they did not want their armor reduction from Alchemist to be countered, as they need him to get a lot of early-mid game roams successful.
Last picks:
Na'Vi: Abaddon
Not very sure about this pick - perhaps they needed someone survivable? Would need some insight on this.
Sigma.Int: Gyrocopter
Gyrocopter was the hardest viable carry remaining in the pool imo, and they needed a very hard carry because of them being forced to pick more support-ish heroes during the draft. They needed something with a lot of damage and teamfight power for late game - hence the Gyrocopter pick.
Final picks for Na'Vi: Timbersaw, Crystal Maiden, Pugna, Outworld Devourer, Abaddon
Final picks for Sigma: Alchemist, Visage, Clockwerk, Nyx Assassin, Gyrocopter
Final bans for Na'Vi: Bane, Invoker, Nature's Prophet, Razor, Mirana
Final bans for Sigma: Enchantress, Io, Chen, Lifestealer, Dazzle
Thoughts about the draft guys?
I also think the Lifestealer ban messed up all their strategy: as they banned Bane and Razor I think they would've loved to get N'aix.
Lastly, I'm happy you didn't write the ending of the game, since I still have to watch it (didn't have much free time in the past two days, and I'll be busy until the day after tomorrow probably), but from what I see Na'Vi's lineup lacks some "strong" pusher like Dragon Knight or those creep-controlling supports that Sigma, doing the right thing, banned. Sigma's lineup looks more solid to me, especially because having Alchemist, Clockwerk and Visage all in the same team already gives you a lot of versatility and damage/initiation throughout all the game. They can easily prevent Na'Vi from pushing too, and we know what happens when Pugna doesn't manage to get tier 2 towers in a reasonable amount of time. I also wonder what their lanes were: mid Alchemist? Mid Clockwerk and off-lane Nyx Assassin? There are at least 3-4 combinations.
Sorry for the late response by the way, but I liked this analysis nonetheless.
Na'Vi: Abaddon
Not very sure about this pick - perhaps they needed someone survivable? Would need some insight on this.
This was most likely based around the idea of Pushing down the Tier 2's as fast as possible with the Pugna. When you think of a Support who can fight under the Tower and just not care, you think of Abaddon and his Aphotic Shield.
With a Timbersaw and a Makansm wielding Outworld Devourer (I just assume they gave Dendi Mek Farming duty, since he could Farm it the fastest) they can fight under the Tower. Add in Aphotic Shield you've got a storng early 5-man Tower Dive Lineup.