Names are very important for many reasons, they can show racial, religeous, class, and cultural affiliations. Sometimes naming can foster a sense of belonging, where persons who share a first or last name feel a sense of recognition and kinship with each other. Increased interactions can only help to foster a better RP atmosphere in the game.
Allowing 'sharing' of names in this way should be possible, as should 'race' naming as suggested above, where names reflect racial traits, in this way a community of users could grow up with a greater feeling of belonging, where naming could play a part in the wider scheme of things by introducing 'families' and 'clans' based on naming, but still allowing uniqueness.
Instead of the present system of wholly unique names, perhaps checking to see if both first and second names are in use, if one is used, but not the other then it constitutes a unique name, and may be used, only if both names are used would it be a problem.