What I don't really understand is why they feel the need to record the communication records of everyone. I don't have a problem with the police being able to tap phones, record internet communications, etc of people they are interested in, in fact that seems a logical set of powers to give them.
Perhaps a better solution would be to make it easier for them to get targeted powers to record communications. For example if they have even a small suspicion Alice was up to no good they could get permission to record and examine her communication. At the same time they could record (for up to a year) but not examine the records of anyone Alice communicates with. If Alice talks to Bob and they have reason to suspect Bob the records could be opened up to them. If they have no reason to suspect Charlie, someone else Alice talks too, then they could never examine Charlie's records.
This gives them the best of both worlds, they have loads of records to examine but it makes drag net fishing harder.