You really think there's going to be a ton of new players after March 15th? Why is that?

Do you think suddenly on March 15th the game will be 'done' and the vast majority of potential players are waiting until then? It won't be done, far from it and everyone knows it.

Is it for some other reason perhaps? I can't think of a reason for someone who wants to play this game not to preorder it now and play it early, learn how it works so when the final wipe comes they stand a chance.

After the game goes 'live' new players are going to be incredibly disadvantaged. Established tribes will have the land they've scouted out and everyone you run into will beat you in combat.