Turn 1 D4 with no mana left over is understandable. What I want to stress more is that your plans also should consider what resources you will have after a D4. A D4 that cost you three or four cards leaving you with more options if only you draw more initial mana (and perhaps the ability to actually pass the turn if you don't) is an entirely different animal than one that cost you six cards and/or Summoner's Pact to cast.