I realize that there currently is an indult that permits communion in the hand, but maybe it is time that is revoked. At Mass this past Sunday, the priest had to stop someone from walking away with the host. Now, granted it is possible that the person in question just forgot to consume it once the host was placed in the hand, but this is the biggest danger that exists with communion in the hand...the possibility of desecration of the Eucharist.
As Catholics, we believe the Eucharist is the Body and Blood of our Lord, and thus should be retreated with utmost respect. Communion on the tongue would go a long way in restoring that respect, although there are other ways that should be implemented to finish restoring that respect. But that's for another time.