I am sure this has been considered - and probably dismissed as tinfoil hatism.
One possible reason why Obama et. al. can't take legitimate steps to stop NSA abuses is that there are things that they know that he does not want to be disclosed. This goes for Feinstein, Clinton, Cheney, et. al.
Knowing that the NSA can and has been dragnetting all, ALL, communications for years it is fairly easy to see scenarios where an newly elected President could discover that everything he has ever said, everyone he has ever talked to is known.
This seems to me the biggest threat from the NSA. Institutional power that is beyond the control of any elected public servant.
All good intentions and objectives could be quickly co-opted by this type of institutional power.
Just sayin. . .