Here is what I wonder; When you didn't have pads were the hits less violent? I have played both football and rugby, and though I got hurt more often in rugby, I think the actual amount of force used, and hence the strain on joints, is less in rugby.
Before pads, the dominant factor in football was the swivel-hipped runner. These were guys like Johnny Blood et al who could run and shift part of their lower body to evade the 'tackles' that were little more than attempts to grapple. The reason these tackle attempts were so weak is becuase there was an equal chance of the tackler getting injured badly as well. It was rare that a defender would try to moves that modern players would use. You can see this in rugby, et al. You grab, grapple, hold and drag. Wheras in the NFL, to tackle you head in at full force trying to use imapct and momentum to bring the player down. It isn't pretty, and the pads favor the impactor over the impactee. Grabbing is almost secondary, but important; the idea is to stop the player with impact then bring him down.
The result? Less bumps, scrapes and bruises, and more potential for long-term and crippling injuries. A rugby player will get more bumps, cuts and bruises than a American football player, but at the end of his career he won't have anything beyond the scars.
By comparison, studies are now coming out showing what many have known for a few decades: Retired NFL players show a host of crippling injuries at ages much younger than they should. Give me some stats of how many retired Aussie Football players need help putting their clothes on at age 50 and then we'll talk.
Its not just the retired players either: NFL players play with a lot of pain, and most careers end in about three years. John Madden has stated "I don't know of any person who could play a set of downs in the NFL and come out physically the same person".
Now keep in mind, this is the NFL. Not little kids in Peewee, or High School, or even College, although
the potential is still there!. In the NFL , you are talking about huge, fast players going full tilt, and they are able to hit you as hard as possible because they know how to use the pads to not get hurt, while the impact you take is kind of random.
So let's drop this 'pads=wimps/no-pads=macho' silliness, shall we?