The real concern on both sides was that the Senate could have changes hands a total of 3 times from Election Day to next January. Consider the following scenario: 1) Talent takes Carnahan's seat immediately, and gives control to the Republicans; 2) Jesse Ventura appoints a Democrat to fill Wellstone's seat; and 3) Republicans win control of the Senate on Election Day, but this doesn't take effect until January. Beyond that, it was possible that the final control of the Senate in January would not be decided until the December run-off in Louisiana.
That agreement between Lott and Daschle wasn't because of a lack of backbone on either side -- it was to avoid the potential chaos that would have resulted if the Senate changed hands multiple times between Election Day and January 1st.