The following article contains spoilers from Nightwing #95, on sale now.
Now that Nightwing's sister, Melinda Zucco, has been exposed, Blockbuster seems to no longer care about subtly taking his enemies down. Nightwing #95 (by Tom Taylor, Bruno Redundo, Caio Filipe, Adriano Lucas, and Wes Abbott) saw him adopt what could be considered a "scorched earth" strategy to fight against Dick Grayson. He has openly attacked the Haven, and threatened to do things that most criminals would hesitate to even consider.
While this may be the first indicator that Blockbuster's empire is on the verge of crumbling, it also makes him extremely dangerous. A cornered animal will fight back when left with no other option, and he has largely been trying to work within the system that he built to get rid of his foes. With that system now falling apart, he has dropped any pretense of trying to outwit his enemies and turned to violence.
As mentioned above, Blockbuster no longer cares about being subtle. With Melinda now revealed as an informant, he knows his time is limited. She has been privy to all of his secrets and crimes in the last few months, meaning that Nightwing is also likely in possession of the files that belonged to former commissioner McClean. He still has people working for him within the government, but outside intervention seems incredibly likely now.
To that end, he has chosen to do away with any multi-layered plans in favor of outright assaults. Attacking the Haven wasn't just his way of saying that the gloves were off, it was also an attempt to draw Nightwing in, and a successful one at that. Indeed, it seems there are no longer any lines Blockbuster won't cross to get what he wants. He actively threatened to murder two children right in front of Nightwing unless he surrendered, and Grayson could tell that he would absolutely follow through.
Interestingly enough, this confirms what serial killer, Heartless, said about him -- controlling Bludhaven is the only thing Blockbuster cares about. It is the only thing he has to live for. Without it, he becomes just another superpowered thug who can easily be taken down by any hero. Being powerless is not a situation he can handle rationally, and as a result, he is not behaving rationally anymore.
Now that the one thing he has going for him is being threatened, he has no limitations on his capacity for violence. He is defending what he believes to be his and wiil destroy anyone who tries to take it away. This is only made worse now that he knows Dick Grayson is Nightwing. A man fighting to protect what he loves will ultimately do anything to preserve it, even if what he loves is being nothing more than a silent dictator using a city's own defenses against it.