I wouldn't blame the format when three strong group favorites (or 4 if we include Belgium) failed to win their group. If they did, then Belgium's route to the final would have been Portugal, England, Spain.
Simply, Belgium were extremely lucky that neither of those three, as well as themselves, failed to win their group. Basically, in every format you'd get these matches if more than half of the favorites fail to win their group.
Only Germany (but only on goal difference) and France won their groups from the pre-tournament favorites. 4 failed. Of course we'd get what we got.