Free agency needs work in this league but I understand why it's often slow or not exciting. Teams are pretty restricted with their budget and have their rosters set. If a big player is potentially in the market, that team isn't going to be able to pick them up. That leaves the only options for that player to be non contending teams which in most cases with free agents is not desirable. They want to play to win. This why you'll often see a sign and trade with money retained and it turns into a trade instead of a free agent signing. 

Give the players more power. Let them have a free agent flex of some sort so that teams are able to sign them. Maybe then we'll see more exciting free agency.