For me, from a handling standpoint, drop spindles are the best way to go vs. drop springs.
Let me try to explain:
Drop spindles shorten the moment arm (the invisible "lever" arm between your roll center and center of gravity) more than drop springs by lowering the center of gravity of the vehicle without changing your stock front suspension geometry. Drop springs lower your center of gravity AND your roll center. I believe a shorter moment arm means the front of the truck will transfer less weight from the inside tire to the outside tire, and for the range of use for your truck, you'll like the handling better with that shorter moment arm.
I believe drop springs are usually shorter AND stiffer, and that sucks, cuz you'll lose suspension travel most importantly in rebound. When the inside tire runs out of rebound travel, the weight riding on the outside tire skyrockets and makes you understeer, killing your handling; and your ride will suffer. Also changes the front/rear spring balance and makes the vehicle act goofy.
Sorry, I could discuss this all day. And you called it "simplistic". 1 vote for drop spindles.