Full disclosure: I'm in this league (LM in fact).
Watt is an absolutely stud DL, but there's no way he'll fetch you an equally studly RB or WR. It's all about the value over replacement. A stud like Rice or McCoy can get you between 10-15 points in a given week. The best waiver wire RBs (assuming there isn't an injury that gives a backup an increase in carries) will get you around 4 points per game. Conversely, the top DL (Watt) is at about 8.5 points per game, compared to the waiver wire guys who score about 4. So if I'm trading Rice for Watt (not what you proposed, I know, but it simplifies things), I'm giving up at least 6 points per week at RB for a 4.5 point gain at DL. On top of that, Rice's best week saw him score 19.5 points and Watt's season high is 11 points, which limits his potential week to week impact.
That isn't to say that Watt doesn't have value. You have to play IDPs, and fielding stud defensive players is a sneaky way to stay competitive from week to week, but when it comes to trades they simply aren't valued as much as skill players. Even if you find a guy like myself that does value IDPs, you'll be hard pressed to trade an IDP for an elite skill player regardless of how good that IDP may be.
Also, as the CJ Spiller owner (as well as the owner of two top 5 DLs of my own), don't even bother sending an email
. McFadden and Murray seem like solid targets though, and much more in line with what I'd be looking at if I were moving JPP. I think I'd have to package him in with another RB though, something along the lines of JPP/Ballard, to get to a fair jumping off point.
16 Team Dynasty League
FGranlund,Yakupov,K.Palmieri,Jarnkrok,Khokhlachev,H ertl,Girgensons,Paajarvi,Beach,Beck,Eakin,Ashton,R undblad,Gormley,Spurgeon,Morrow,Schmaltz,Campbell