Complete nonsense I'm afraid. If Spain had beaten Russia and Germany topped their group we'd have had a final 8 of:
France, Uruguay, Brazil, Belgium, Spain, Croatia, Germany and England.
That's a fairly strong last 8 but it's nonsensical to change the format because some big teams underperformed
The World Cup format is not designed to ensure that the strongest sides do not play each other until as late as possible - far from it.
Alternative tournament formats could ensure this.
Your observation that - if only the better sides had won their matches - we'd have had better matchups - is misplaced.
The point being - that much better tournament formats exist - mathematically rigorous formats - to ensure that we see the most compelling matchups possible, with the better sides avoiding each other until the final stages of the tournament.
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The chief problems of the WC format in this regard are:
1) After the knockout stage, the placement of the surviving sides depends upon performance - finish 1st, you're on one side of the bracket, 2nd, you're on the other. This creates the possibility that most or all of the top teams finish on the same side of the bracket following the group stage (which happened in this cup). Moreover, it creates the possibility that losing a match is favorable to winning if your goal is to go as far as possible in the tournament (to wit, England v. Belgium in the final group stage match - the winner, loses).
2) Seeding is based on a flawed FIFA ranking system. Better to have a wide selection of football experts meet and force-rank all teams from first to last to determine seeding.
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Admittedly, changing the format of the WC along these guidelines won't happen - a) b/c there's little dissatisfaction with the existing format; b) b/c FIFA is still corrupt at the highest levels; c) smaller countries have equal voting rights as large - and those smaller countries would want their sides - most likely inferior sides - to have the best chance of advancing - diametrically in opposition of having the best teams face each other as late as possible.
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In short, a system designed to protect highly ranked teams, giving such teams the best chance to advance in spite of the randomness of lose-and-go-home exists; such a system is employed in USA college basketball. Such a system could be applied to the WC, but won't for various reasons.
The existing WC format does very little to protect the highest ranking sides - in fact, the ranking process itself is flawed.