If I had to choose between the 2 it would be WCW and I know you said 2001 but, I would try the save the company before it got to the point where it was at in '01.
Here's a few steps I would take:
1. The NWO wouldn't have lasted as long as it did (including the rehash of w/Bret, Jarrett, Nash, etc.,) when Goldberg beat Hogan that would have been the end of NWO.
2. Cut Hogan's contract/creative control in half or put him out of the company.
3. Slowly start pushing some of WCW's work horses like Benoit, Bret, Eddie, DDP, Stenier into the main event and make them strong competitors use guys like Nash, Hogan, Flair etc., (more established guys) to build the previous names.
4. Get rid of Russo/Ed Ferra hire some old wrestling heads that actual about making the product better.
5. Either move Nitro to a different time slot on Monday's or move it to Tuesday nights.
6. Put more emphasis on Thunder like WWE did with Smackdown when it first started.