Why would I think that? During his campaign in 2008, he switched his stance on the issue and voted for more surveillance - something he had promised to vote against only months prior.
Since his time in office, he has stuck to this reversal.
This is nothing new - he's been doing this for the last 8 years.
Therefore he's exploited the unilateral powers given to the executive branch more than any other president in history. So even if Trump does even half it won't seem so bad.
The best part is that he's handed plenty of fuel to any Russian who wants to dismiss their own governments abuse of power by pointing to the US. And they do this at every turn. So despite his tough talk on Russia, Obama has done more to make it easier for Putin to do whatever he wants than anyone.
The problem with a 'good' seeming guy going to such extreme lengths of power is that it legitimizes the bad ones who do it. So the problems should not only be analyzed locally but also considering externalities.
This is why ideological consistency is critical. If you're going to be abusive at least be honest about it. Fortunately we won't have this problem with Trump, he can't help it even when he tries.
[1]Clinton Slams Obama for Voting “for” the PATRIOT Act at ABC-Facebook New Hampshire Debate - https://www.wired.com/2008/01/clinton-slams-o/