Some folks like a quieter server and knowing many of the other players, or at least recognizing them. In particular I prefer that the general chat, help and LFG messages aren't screaming past. As a personal preference you can choose your shards, you can even shard hop. You can invite other players to join you on a shard. Point is, the thing you want- higher population- can be found elsewhere. Go there. But please don't try to change the shard(s). There is NO reason to consolidate them.