Here is my creature-less deck.
You have a lot of cards that do not impact the board and too many situational cards. Here are the cards I would cut
Reprisal
Solemn offering
Meditation puzzle
Sanguine bond
Skullcrack
Suffer the past
Blood tribute
Darksteel ingot
Elixir of immortality
You definitely want the full set of shock and resounding thunder and more dual/tri lands in the mana base.
I would also add Kozilek and obelisk as finishers and maybe go down to 1 wand.
Deck is creature-less, so no Kozilek, however the Obelisk fits perfectly.
The cards you mentioned not having other than Reprisal, Skullkrack and Darksteel are all win cons tied together. As it's creature-less deck I had to use lifegain and drain to suppliment. Skullcrack has so many diverse uses that I cannot see myself trading it out for resounding thunder.
As far as Tri-lands, there is no Mardu shard land. I find the deck runs best when my land is available and not coming in tapped.
This deck is VERY, very situational and not just due to its own cards. Winning depends as much on your hand as your opponents.As a creature-less, some of my opponents end up with dead cards in their hand that may have helped their scheme.
This deck is not meant to be a majority winner, but was a challenge I laid out to myself. Every game ends up going quite long and it's win rate is about 50% or less.
All of this should have been put in my deck post above but I was sleepy and kinda drunk