This one lacks ordering. It's not a problem for Russian names as the rules are fixed, but may be a problem for other ones.

And how would it scale? E.g. John Ronald Reuel Tolkien and George Herbert Walker Bush have two middle names, while full name of García Márquez is Gabriel José de la Concordia García Márquez. Markup handles this uniformly creating only as few metadata records as necessary, but a field-based model will need fields for all of this that will stay empty most of the time and likely some meta fields to set additional quirky flags.

Regardless of how complex naming schemes you need to support, you just make it more complex and harder to query by storing tag names and character indexes and whatnot.