We've been misled
Liberty says that the Government has deliberately floated the idea of the most "outrageous, even impractical powers" to distract from the meat of the bill: by spouting rubbish about banning encryption - something that'd cripple our financial services industry for starters - and monitoring individual social media posts the government has been able to distract everybody from the things it really does want. According to Liberty's Shami Chakrabarti, the Home Office is guilty of "frantic spinning": deliberately telling journalists porkies about powers they had no intention of keeping in the Bill so that the Government could appear to back down without diluting the key bits of the proposals.
It'll be abused
On average there are four data breaches a day, Big Brother Watch says, and in 2013 it emerged that the Met was using surveillance to create files on journalists detailing their medical history, family circumstances and sexual preferences. Those journalists weren't implicated in any crimes; the files appeared to be a form of insurance should said journalists get too curious. Liberty reports that GCHQ has spied on the private communications of Amnesty International and other campaign groups, and the police are known to have spied on and smeared the parents of murdered teenager Stephen Lawrence.
Elsewhere councils have used surveillance powers to spy on employees suspected of lying about their car parking (Darlington), hours of work (Exeter) or sick pay (Hammersmith and Fulham) and to spy on people suspected of flouting the smoking ban. We're not condoning any of that behaviour, of course, but it's hardly the organised crime, global terrorism and drug smuggling the powers were supposed to fight.
It's the wrong answer
The security services already intercept astonishing amounts of data, and they don't have the resources to process what they've got: for example, the killers of Lee Rigby were well known to the security services, but they were classed as low risk and weren't monitored due to lack of resources. It's hard to see how upping the amount of data collected is going to improve that.
The legislation is a proposed bill, so it'll be scrutinised by MPs before it's voted. Previous attempts were defeated by opposition from the Lib Dems, but there aren't so many of them around these days. Most observers believe that the Bill will become law without too many changes.