I'll throw you my two cents as well.
I think frankly that CLG is the only team with a group that gives them the opportunity to leave groups without too much problem. KOO Tigers gets out of groups for sure, I'm positive of that one, but When it comes to the Flash Wolves or CLG, I'm not 100% sure which one makes it out. CLG has always had a habit of choking under pressure, pair the fact that this will be the most pressure the team has ever been under with them not having their starting jungler and having to make their mid laner sub jungle, I think there's a lot of potential for them to not leave groups.
For group B I say that Invictus Gaming makes it out for sure, the Chinese teams are all very close in skill level, so to say that any single one of them is substantially better than the others is a bit of a leap, that being said, I think that the Chinese teams that made it in are undeniably stronger than the western teams. The curiosity for me is Fnatic or AHQ leaving groups. I genuinely believe Fnatic is the western teams only hope of actually leaving groups, but I'm not sure if they can edge out AHQ, I haven't followed AHQ in recent months, but I know they did perform better than Fnatic in the groups stage at MSI, albeit by a single game, but nonetheless. There was no losers bracket to go off of between AHQ and Fnatic, so it'll be interesting. C9 stands virtually no chance of getting out of groups, they're just not strong enough as a team yet, the fact that they made it into worlds is bewildering to me.
Group C, I completely agree that SKT and EDG come out of groups, I'm curious to see how that match goes along, as SKT did lose to EDG back at MSI. H2k takes 3rd, as the only IWC team that is relevant in this tournament is PaiN Gaming, short of some sort of blood sacrifice neither team leaves groups. Bangkok Titans simply don't have the ability to compete at as high of a level, they just don't have the resources at the moment.
Group D is the most disappointing group for me, I'm a huge TSM fan, but I don't think that they make it out of groups. For me LGD takes first in this group, KT Rolster likely takes the second. Origen has a lot of experience on their side so they could pull something, and TSM typically has a history of very strong performances when coming out of a long practice for a major tournament. I think they just need to have some confidence and just maybe they can pull something off. I'd be happy to see either TSM or Origen leave the groups stage, obviously preferring TSM, but I think it's a long shot for either team to make it out.
TLDR:
A: Koo Tigers
Flash Wolves
CLG
PaiN Gaming
B: IG
Fnatic
AHQ
C9
C: EDG
SKT
H2K
Bangkok Titans
D: LGD
KT Rolster
Origen - TSM (I genuinely can't deicde, but I think I'd give the edge to Origen unfortunately. Jungle/Support synergy is just far better on their side than on the side of TSM, and frankly I don't know that Lustboy is working well with the team any longer. He's a tremendous support, but seems to have fallen out of sync with the rest of the team lately.)