Many on here have replaced theirs. I have replace several. I have a brand new Raptor that came with the dreadful WFCO converter. I didn't even use it one day and I have unplugged it and installed a Xantrex TrueCharge 2 charger right next to the batteries. Third WFCO I have replaced. The WFCO was chugging away 4 amps/13.6 volts the whole time before it got the boot. As soon as I turned on the Xantrex, it went up to 37 amps/14.4 volts.
So you may not have to deal with all those wires if you can install a new converter close to the batteries.