**Well, you know, to me, it's "metrication? yuck".  I was thinking about it and I think the reason is that change-of-state verbs, for the most part, don't end in -ate, so the verb "metricate" sounds distinctly inelegant.  Change-of-state verbs normally end in -ify or -ize, so it should be "metrify" or "metricize".  "Metricize" is probably better given that we want to be able to use it intransitively, but that leads to the awful "metricization", so better to go with "metrify" and "metrification".  That's just to my ear, but I would expect that most Americans would hear it similarly.