A warrant needs to state with particularity the thing that the person doing the search is looking for. It also needs to state where the person searching can expect to find it. There is no way that a warrant that allowed search of 8,000 computers in 120 countries was specific enough to comply with the law.
The FBI has been prioritizing security over individual privacy since 2001. Over time, the intrusions into personal emails and phone calls have increased and have inspired calls to halt large-scale collection efforts, such as the NSA program. A blanket warrant to hack thousands of computers cannot possibly be targeted at potentially "guilty" individuals. These should be banned.
Expansive warrants should be banned. In fact, any warrant should be limited to the scope of what the investigation is. These types of warrants are nothing short of a fishing expedition. It is high time to put an end to this kind of massive overreach of the government and limit its powers.
If they can show proof that it was necessary to search that many computers through one search warrant, then I don't think there should be a problem. This saves a lot of time and paperwork, not to mention money, in securing warrants. I do see, however, how they may have trouble explaining the necessity for this.