The odds on maxroll don’t even show for some low level set items on Normal such as Arctic Horn. Ironically the long-term NM & Hell players get a ton of them dropping instead of rares or useful stuff but new players trudging sloooowly SSF offline will never see them until they are worthless junk compared to runewords/crafted/random rares. Was this by design?
The drop rates are notoriously low in this game for pretty much everything except potions and gold. Sometimes it seems as if the game knows what you want, and it purposely does not drop it. For example, when you realize you’re out of town portal scrolls when you need to go to town, yet for some reason the monsters you have already killed and the ones you kill for the next 5-10 minutes never drop one. 
Low level set items are something you might collect for the sole purpose of starting a different character with. The angelic set is one I like to collect, as it is a well rounded and versatile starter set for many classes even without all pieces equipped.
I agree that low level set items should drop more often in normal, at least in LoD anyway.
I have two toons for each class (except Assassin) and am taking turns leveling them up. I load up every toon with poisoned throwing knives as it’s more powerful and better than their special beginning class attacks. Don’t even need much Dex. DPS still seems to out-pace & devastate better than most spells/skills that are sloooow. And I dress them up in gear that is a hodge-podge of cheap runewords, crafted, socketed, and MF rares. Stash, mules, loot selling, and outfitting becomes more drudgery though.