I think the flow of the game is just fine up until the last 2 minutes of a game from what the non NBA fans say. I'm actually ok with how the last 2 minutes go, but I could see improvement there to capture a wider audience.
However I also hear from some people only the 2 minutes of a game counts, and don't bother watching the rest. I see their point too but I enjoy watching the up and down flow to a game.
Maybe to appease both areas shorten the game to 40 minutes, and limit a team to only 1 timeout in the last 2 minutes. I don't think everyone would agree to a shorter game, but limiting a team to 1 timeout with 2 minutes left in each half you might get more people on board.