"Using the same tactics to undo much of what Obama has done, that he used to do it in the first place, is not only permissible, but totally necessary."
Obama has used illegal tactics. for us to use those same tactics would be illegal.
It is true that most in the GOP have been not only unwilling to use their constitutional authority to combat and halt it, but have been unwilling in large part to even call him on it.
That's why I say the answer is the constitution. The legal authority to stop him is already there. We simply have to elect people who will use it...or throw those bums out and find those who will.
80 Illegalities of the Obama Administration
http://www.jeffhead.com/80-illegalities.htm
If his tactics are allowed to stand, then they have not been deemed illegal or unconstitutional. With politicians and all the immunities and exemptions they allow themselves, they can get away with a lot unless someone takes the initiative to challenge them.
And, yes, definitely use executive orders to reverse anything done by Obama that can be reversed with EOs, and even push the envelope to undo more of his damage.
There are simply areas where a president can act and little can be done about it short of impeachment, and that is almost impossible to accomplish. It's just not all neat and pretty with well defined corrective measures, and what have election victories gotten us so far? A strong president could reverse far more than any Congress we're likely to elect.