I own an 05 and I've been a master GM dealer tech for the past 13 years.
Most of the issues you mentioned are small and easily fixed. Throw on a set of 2/7 injector connectors, pull the zip tie off the alt/ FICM bracket and you're good to go. I haven't had any issues with mine. Doesn't run hot (that was a certain # of late 04/early 05's) and pulls my big a$$ 35' hauler anywhere I need it to go. I would like to gain mpg and get cooler EGT's for towing. I'll be talking with you soon.
I, personally, have seen quite a few more issues with the 06-07.5's than 05's. Lots of turbos, EGR valves and EGR coolers.