I never quite understood how card advantage wins the game without a very specific setup, so for me Loremaster has a place in a constructed deck, but not in a draft (particularly because of its reliance on allies which are hard to draft right).
Harrow is always good, but rarely excellent -- unless you go for a very landfall-reliant deck which, again, is hard to decide at first pick.
The tsunami... I'm intrigued by it. It might combo well with any landfall cards or with the common spell-lands -- for example Teetering Peaks or Turntimber Grove (which is relevant to another question). These are all easy enough to draft later on, so I think I'd go with the Tsunami here. At least until I lose miserably with it.