KO bonus clause

Is there anything preventing a KO bonus clause in a boxing contract? The addition of a KO bonus would be great for the fans and promoters both. Promoters win because it's a way to encourage their most boring fighters to be more aggressive, and it's also an excuse to pay the boring fighters less (which they deserve to if they can't win fans). Of course managers would be against the idea, but with a boring fighter the manager has less leverage so there's a balance. Let's face it - boxing is a business first and the sport depends on fan friendly fights. Think of all the elite level fights that are not being made because of fear of having a boring fighter win the championship and then having to promote him. (i.e. Rigondeaux ) Fans win because it encourages fan friendly fights. I'm a hardcore boxing fan and I can appreciate any style but it is hard to watch 2 defensive fighters in the ring at the same time - Even the hardcore fans can agree on that.