This is a basic Hog cycle deck updated to fit the new meta. This deck performs great on ladder because of it's defensive capabilities mixed with the sheer speed of 3.1 cycle.
This deck was recently played by Senser to achieve number 1 on the global leaderboard.
There is no "most valuable card" in this deck as every deck has power potential. The spells, in particular, should be used wisely. Tornado to activate your King Tower as soon as possible. Using Executioner Tornado to chop down swarm cards is incredibly effective for positive elixir trades.
Hog is, of course, your main win condition. He can be used with Knight (vs Tornado), Guards (vs tanks), and Ice Spirit (vs air units) at the bridge.
Log can be used as a predictive play behind the Hog. Just be sure to identify your opponents small cards early (ie, Goblins, Guards).
Do no use predictive Log if your opponent has a defensive building. Zap works well subbed for Log in this deck if your Log is under-leveled or you have yet to unlock it.
Guards can be a strong card in this deck. They are great on both defense and offense. Combo with Hog for an offensive push or drop them on defense to stop a push!
Poison is your big spell in this deck. Use it only for value on offense during the first two minutes (single elixir) - in double elixir time you can get more aggressive and use poison on offensive pushes for less value. Don't be afraid to use Poison on defense!
Be cautious and feel our your opponent. After you know their small cards and their spells you can proceed with better knowledge and confidence on offense. After you know their win condition be sure to save your best card to counter it and switch up locations.
Late stages with this deck you can up the tempo and aggression! Lay down an occasional predictive Log or Poison. Keep in mind that offense in this deck often comes on the counter attack, meaning you successfully defend with Guards/Knight/Executioner and cash in with a big offensive push combining Hog & Poison with your leftover defenses.