I'm in the process of finishing the basement and only have the stairs left as far as framing.

What do you think, rework the stringers that are here or tear them down and rebuild them? They will remain open and have a railing running along the landing and down the stairs. My main concern is how the original framers basically nailed the stringers into the plywood (see image st4) and the outside stringer should be flush with the outside wall which should have had the 2x4's 45'd under the stringer.

http://www.bergsonline.com/st1.jpg
http://www.bergsonline.com/st2.jpg
http://www.bergsonline.com/st3.jpg
http://www.bergsonline.com/st4.jpg
http://www.bergsonline.com/st5.jpg

Try re-working what you have. (stringers)
That wall along side the stringers needs to be removed and done properly. That's horrible.
A couple things you can do is remove the stringers, add a 2x12 under the landing flush with the framing so then the stringers can be re-attached to the 2x12 and not plywood. Move the outer stringer flush to the landing and then space the middle one accordingly. Then rebuild the stringer wall how you need it to be to make everything look good.
You may want to leave a 1/2" space between the inside stringer and the wall so it makes drywalling so much easier. You won't have to cut the drywall to the stairs. After that, then you can attach the string to the wall.