I don't think Walter would trade Jesse for Todd. Todd's a bit of a wild card, and Jesse is the one who keeps coming up with ideas. In fact, I think there's a good chance Jesse becomes kingpin (and/or kills Walt) at the end of the show.
Regarding the wiretap: I'm surprised Walt wasn't worried about fingerprints. It's at least somewhat possible that the police chief's office is checked for bugs on a regular basis.