That was my old harness and I ended up re-doing it to simplify it. Also, about 40% of what you see there is extra loom and wire looped back on itself so I could re-design it later if I wanted to (which is a good thing I did it that way, because I needed the extra wires and slack later on)
Here's where I'm at now for my final harness that deals with both the ISIS and digidash
Could I trim it down more? Absolutely - note how many "dead ends" there are in it (i.e., excess wire incase i need it down the road) - however I like it this way because it's easy for me to work on.
If I got rid of the terminal blocks and soddered te stuff together in a loom all I'd have is 1 piece of wire loom and that's it. However, it'd be more difficult to work on in the future. Also, if I didn't double up wire (the digidash GPS unit has about 20ft of wire I had to double up into the loom) I'd cut down there.
I choose to do it this way to make it easier to work on down the road.
It's silly to say the above is what ISIS represents; no, what ISIS represents is somebody (i.e., me) who's NEVER done any wiring before, who didn't even know what words like 'crimp', 'strip', meant, was able to wire a car and have EVERYTHING working perfectly the first time through.