There’s something cool about the D2 rune system, but there’s also a reason no other games have copied it. Runewords are fun because they give you a big reward you can make incremental progress towards, and they give a bunch of trade currencies that are harder to get than gold. The problem is that they have to be overpowered to be worth the extra effort and to drive the market value of the runes. But if they are overpowered, then they restrict your choices, just like D3 set items did. You have to get certain runewords and when you do there are no more items of use in that slot. If they brought back runewords and the items they produced didn’t have an explosion of affixes on them, would people actually enjoy it?
One place I could see either runewords or set items being interesting enough to be worth using but as an alternative to legendaries and uniques instead of a superior replacement, is if they didn’t have an aspect, but instead had a ton of affixes. So imagine that they got the usual 3-4 base affixes, 2 affixes from the tempered pool, and then another 3-4 affixes from either pool. And if you could then make them on different item bases to give some flexibility like runewords often had, that could be an interesting space. Same with set items, where you could imagine having set items that drop with 2 random affixes like rares, but then for each additional item of the set equipped it adds a fixed-roll affix or two.
I do wonder, based on there being a new tab in the jeweler and based on some of the cryptic comments from devs and partners, if we are getting some form of rune words or at least jewel crafting.