Frost can potentially still make it if they make it through regionals, but I wouldn't say that they're as consistent as people give them credit for. I think teams have figured out by now that target banning Madlife is the only way to deal with him. Also, CloudTemplar has bad earlygame impact, and the midlane issue with Frost is still there. Rapidstar is very inconsistent and GBM is subpar on everything except Orianna. How far Frost can go depends mostly on how hard Madlife and Shy can carry them and also whether they can get off good teamfights or picks (they are one of, if not the scariest teamfighting teams in the world). A huge reason they got 3-0'd by KTB is because InSec flat out beat Shy in all three games and they also took away Thresh, Blitz and Sona from Madlife every game.
I think if KTB play vs SKT like they did vs Frost, it will be an easy 3-0 or 3-1 win for them and they will go to worlds, and the third spot is a tossup between Ozone, Blaze and SKT in the regional qualifier.
If SKT wins against KTB, SKT will get the second worlds spot and again the third spot is a tossup.
The Korean system is really weird imo, they should have straight playoffs instead of using circuit points.