Many of my friends and I do not enjoy the randomness of the global effect or "scenario" cards played at the beginning of each round in High Noon and a Fistful of Cards (Wild West Show cards are similar, but these scenarios do not occur at the beginning of a round for a round, but rather begin and end when certain cards are played). However, we still enjoy the idea of these scenario cards. Our solution is to pick the deck(s) we wish to play with at the beginning, shuffle this deck, and flip these cards over in a sequential order (with High Noon and Fistful of Cards being last in this order). At the beginning of the second round, the effects start to occur each round in this sequential order. When a card is used up, it is flipped face down to indicate that it has ended. This way players can prepare for future rounds, and yet still have variety added to BANG! with these cards.
This might be worth trying out if you are frustrated by the randomness of these decks too.