Get rid of bad mechanics that kill the game. I suggest the following:

Heist. I want to play my deck vs an opponent's deck, not part of my deck vs the other part of my deck.

Companion. How is it fair for an opponent to have an untargetable extra card in hand.

Get card from outside the game. Now this is just stupid. How is it legal to grab a card from basically nowhere to put in your hand. why not play a land deck with all your staple cards "outside the game" and untagetable.

Leylines. Strong abilities played for free before turn 1? Just leads to more conceded games.

Self-combo cards. Remove cards such as Thassa and Goblin Charbelcher that combo with a deck concept instead of another card.

Denial decks. Somehow limit decks to where they can't stop the opponent from playing while taking 10-minute turns.

Netdecks. Make a format for everyone who copies the 25 top decks to play so the rest of us can have a more enjoyable experience. This is the reason I went to one FNM and never went back.

Shuffler. It sucks, ask anyone.