It's an artifact for decks that care about it, it's indestructible for those that use sweepers, and it's hard to answer for those that care
The reason for the Titanic's climb will be pretty obvious if you were paying attention to the big Magic news last week
He would deck you by playing Swords to Plowshares to remove all your creatures from the game, thus shrinking your library so that he would eventually deck you
Summary One of the best replacements for Dockside Extortionist is Ancient Tomb, generating two mana at the cost of two life
The best reading you can do on this are Aaron Forsythe's columns
For five mana, this white Planeswalker enters the battlefield with six loyalty, possessing a +2 capable of diverting attention from its controller for a turn, forcing each creature the target opponent controls to attack Gideon if able