Let me get this straight
So if :
1) I can identify a device in the path of traffic I am interested in - quite feasible although sometimes the complexity of ISP networks with failover and load balancing can make things hard, but ok I'll give you this as "possible"
2) Exploit some sort of vendor weakness in that device you've identified - ok so you've now got admin control of the router, I've never seen such an exploit in a industrial grade router, but maybe...just maybe
3) Copy traffic to a host you control - ok now you've lost credibility, unless you are making the assumption that you've got a owned server on a port that you can swing port mirroring onto without any alarm bells going off.
Really, to be honest this is about on par with my plan to take over the world:
1) Gain access to White House
2) Steal nuclear command and control briefcase
3) Send emails to world leaders saying I will nuke their ass if they don't pay me a billion euros worth of uncut diamonds
Shiz, I've just discovered a major flaw in global security! Quick, phone the newspapers!