Instead of first and 10, in football, it will be first down and 9.144 meters to go. No, it wouldn't. If sane people were to "metricize" football, the gridiron would be lengthened to 100m.
Years ago when the US tried (and failed) so make the metric system socially acceptable, Saturday Night Live ran a fake commercial introducing the Decibet - a metric alphabet with only 10 letters. Here is one of them:
