Lack of Latino fighters. By and large they're the only ones still in it for glory (with a few exceptions like Froch, Hopkins, Pac, etc). Everyone else is into stat padding to get the big payday and retire.
The problem is that the dominant champion we have is not intent on going in guns blazing. 1986 - 1990 was the exact same way. An overtly dominant champion with really no end in sight for his reign. The difference was that he went blood and guts every fight. Now 1980 - 1985 on the other could very well be a twinbrother of 2005- Suoer skilled champ, who kills in the ring but gets killed in the public opinion because he can't hold a candle to the fighters of yesteryear. History repeats.
Actually, it doesn't matter if the dominant champion is not intent on going in guns blazing. We already know he's going to jab you to death. What we need are challengers with balls. You see Arreola fight like a man even while getting himself beat the crap out of? Yeah, we need more like him. It's not that the HW division is bereft of talent. It's that almost everybody that Klitschko faces is afraid of them whenever they actually do fight. When they do fight, it's the challenger's job to make a fight out of it. The champion is already boring as heck, except Vitali. And that won't change. We need more hotblooded Mexicans in the heavyweight division.