Start Before Merge?

Does it make sense to start a new character on Deathwing or Ragnaros before the server merge, or just wait?

If I wait, would there be more players at lower levels? Not sure if the merge is going to be like a big announced event like Lorderon, or just going to happen one day.

Thanks

Leveling should not take you more than a few days on a x7 realm. Also, it is not 100% sure, but generally these minimum transfer levels are really low.
If I were you, I would start it.