There's got to be over 100 threads on this topic on this Forum. Do some searching and you will find the information and opinions that you are looking for. Try the search string key words 'Z55 Suspension Delete'.
Bottom line: There are folks who support keeping the GMC OEM active suspension, and there are folks who support moving to a passive suspension system. At this point, you could say that it is a matter of personal preference. Form my perspective, I've had both the active and passive suspensions on my truck, and, IMO, the active suspension is a much better system.
Some facts: If you go the passive suspension route, you will need to purchase and install 4 electrical resistors, one for each wheel, to disable (or fool) the truck's electronic into thinking that you still have an active suspension, and eliminate the dash warning light. To go the passive suspension route, you will have to change the rear springs to a stronger non-active spring GMC specification, since the active system uses the air shocks in conjunction with softer springs to provide the necessary lift and ride quality.
Please give us your thoughts, after you've had a chance to review the applicable threads in this Forum.