It also reduces the possibility to repair your own mistakes. Argentina could, Germany couldn't but if they had won against South Korea they would have went through. You make one mistake in a single match and you're home before you know it.
Train and Kwyjibo are right, I've read that they're considering penalty shootouts for matches that end with a draw, to always have a winner.
I hope the experimentation fails and that we go back to the 32 teams format in 2-3 editions. This also limits the possibility of host nations, how many there are out there who can keep that many teams? the triple bill of Usa / Mexico / Canada is silly, as much as it's a chance for continental unity, but USA is hosting anyway 60 matches out of 80 so it's not a trinity but "We play in the USA, and the games that can't be held for physical limits will be played in our neighbours stadium".
What's next? Spain, Portugal and France co-hosting? all the nordic nations of Europe hosting together? Chile, Argentina and Uruguay south-south American bid?