Вам не нужен плагин.Команда ex :center делает именно это, центрируясь на заданной ширине, которая по умолчанию соответствует вашей опции textwidth или 80, если последняя установлена на ноль.
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When that your flock, assembled by the bell,
Encircled you to hear with reverence
Your exposition on the holy text
Than now to see you here an iron man,
Cheering a rout of rebels with your drum,
Turning the word to sword and life to death.
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:%ce 70
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When that your flock, assembled by the bell,
Encircled you to hear with reverence
Your exposition on the holy text
Than now to see you here an iron man,
Cheering a rout of rebels with your drum,
Turning the word to sword and life to death.
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