We want to solve the day one problem of shards […] Day one is probably the worst experience you’ll ever have because you don’t know where your friends are, you don’t know what server they’re on, your guild tells you ‘everyone get on this server’, but by the time you get home from work that night the server is full and doesn’t let you create characters there anymore, so you create a character on another shard, but three days later you have to ditch that completely to play where everyone else is.
Doesn't the same logic apply to restricting each race to a specific faction? You create a character, and later find out you can't play with your friends, because they've created their characters in different factions? Now one of you has to sacrifice the time spent on your first character to create another character so you can play with your friends. How is this any different?