The problem is that the NSA and GCHQ through their spying programmes have now given a whole load of regimes all over the world a very valid excuse to do some very bad things both in terms of snooping on their own citizens and restricting the flow of data beyond their borders for allegedly altruistic purposes, but in reality in some cases, particularly the likes of China, Russia, Iran, Saudi Arabia etc etc, it will come down to a crack down on freedom of speech and spying on their own citizens.
The sad thing is that the big western intelligence agencies have basically given everyone else carte blanche by setting a precedent and then arrogantly pushing that notion that it's somehow OK to just override people's privacy and democratic rights on the basis of nanny-state protectionism.
These snooping organisations have also done the US IT industry a huge amount of damage by forcing it to be complicit in some of these spying systems through legislation.
Unfortunately, it's getting to the stage that you can't really trust IT equipment from anywhere anymore. If it's built in China, there's a risk, if it's using US designs/software or is from a US company, there's a risk, if your data's trafficking through the UK or even France there's a risk it's being tapped... the list is endless.
I can fully understand why you need to go after terrorists, pedophile rings, all sorts of organised crime and drug gangs and other terrible things, but there's an element of data-trawling just because we can and because the technology exists to do so.
The counter risk is that because there's no clear oversight over any of these agencies, you've no idea what's being read in terms of intellectual property, financial information, sensitive government communications that might give a state competitive advantage, personal emails that could be used to blackmail someone or sway political campaigns etc.
Also, where does national interest end? Many countries would see the success of their own businesses as in their national interest and legitimately so. Does that mean that it would be OK for a spy agency to provide information about competitor countries' commercial businesses for example? I'm not saying that the US necessarily does this, but there are many other countries where it's hard to know where the state begins and the corporate entities and businesses end and they run almost more like companies than countries, China in particular is a lot like this.
It's a total mess!