Q u o t e: To play the devil's advocate, in a way, salvage material isn't really a random drop. At least not in the sense that a rune is. You have control over where you get the material and how much you get.
Well, you're just arguing semantics now :p The analogy was to compare something relatively easy to obtain that can be constantly improved that we're already familiar with (runes). Will we get scraps more frequently in D3 than we got runes in D2? Probably, that's not important. We can discuss how much time and effort will be involved in obtaining enough runes to make it worthwhile vs the time and effort in scraps.
Depending on drop rates either system could go either way, but both systems involve fairly common items a user can collect and improve. In D2 this common item type wasn't worth collecting at the lower level when you were at a higher level and I'm going to assume Blizzard isn't going to want the D3 players collecting scraps from level 10 items when they are level 70 :p I suppose they could adjust the numbers to make it that way but that doesn't really sound like a good design decision to me :p
Q u o t e: It won't be worth it to some people, but it will for others. If you're stuck because your weapon isn't up to the job and you're having bad drop luck, you can still work at gathering the resources to craft a new one by salvaging the gear wherever your current weapon allows you to play.
Well yes. For example if you're in a level 50 area that's just too rough for you you'll probably go back to a level 40-45 area to collect scraps. This, if understand is what you guys are saying which makes perfect sense. What I'm saying is that it most likley won't be worth a level 50 player going back to a level 5 or level 10 area to farm enough scraps to put together some decent level 50 gear. It make sense that farming that level 40 area will get you a significantly larger volume of higher quality scraps than that level 10 area and this is why I'm saying those low level scraps will be worthless to higher level players just as El runes are useless to someone trying to create an Enigma