The problem here is that the parties that are going to get hit with those patents probably don't even exist yet. Your typical patent troll buys patents that have value, the filing was done in bulk in the past, then by the time the state of the art has progressed for a bit (much more than half a year) they look over their portfolio and decide which patents can be harvested.
Some patents trolls will buy up selected patents that have been filed by others.
So the opposition applications will likely not be done because you'd have to oppose a whole ton of patents more or less on principle without knowing whether or not those patents would ever be used to litigate.
The patent office should get better at doing its job and should not simply approve the vast majority of what goes past their desks without doing actual work, and should make the filer pay a stiff fine if they miss disclosing prior art should the patent be refused or overturned.
Not that that is ever going to happen, but the current system favours the applicant way too much.