I think it’s important to go over why runes and runewords were so important in Diablo 2. They had three major features: They were useful in the early game for specific coverage, there were mid-level runewords that could be used in almost every build, and the endgame runewords were build-defining. I want to cover these features as well as how they might be ported to or improved in D4.
Early game usage of runes is pretty much the only time when the individual effects of the runes are used (with a few end-game exceptions). Playing a caster? Socket a few Tir runes to get mana back. A melee character? Put a Tal in that weapon and start poisoning your enemies. Going up against Andariel? Find some more Tals and put them in your armor!
This is one point that I think already looks viable in D4. One condition rune, one effect rune, and an early character should be good to go. Picking up early loot and figuring out how to make it work for a few levels until you find something better feels great. Found Eth and Thul? Change your playstyle to include short periods of inactivity - cast buffing skills, summon pets, etc for 3 seconds to activate that shield. Found an Eld and Ko later? Put on some more tanky gear and get up close and personal with monsters!
After a few levels, you start having the ability to narrow down the type of gear and the build you want to use moving forward, so individual rune effects start becoming less important and runewords themselves are a great way to define a build. If you find the runes for Spirit and a socketed sword, your caster is set for the next 20+ levels. Edge can carry a ranged character for a while, while Strength and Steel can take the place of any early Rares that are now showing their age. Aside from covering slots that need an upgrade, runewords also helped with general quality of life. Put a Harmony bow on your merc for Vigor if you feel like you keep running out of stamina. Make yourself a Peace to summon a Valkyrie for the extra meat shield. Not to mention Insight, which ends mana woes for all but the most spell-intensive builds.
Hopefully higher runes will have more powerful effects or the rune effects either scale with character level or the runes themselves can be upgraded, because as it appears right now, those bonuses will taper off quickly. To keep with the Diablo feel, I’d prefer to be able to upgrade the rune effects with crafting materials or something similar rather than having them scale automatically.
Endgame is of course when the higher runes come into play. Breath of the Dying, Dream, Brand, Enigma, all of these and more are end-game items to be equipped on the highest level characters. Virtually all of them have unique or cross-class effects, like the Paladin’s elemental auras, the ability to use the Druid’s Bear form, casting Bone Spears, or inflicting a Necromancer curse on enemies. Most of these effects are a primary or secondary reason to have the item equipped, but they all have other effects, such as massively increased damage, life, defense, or attack/cast/recovery speed. It’s the combination of these unique effects with good mechanical bonuses that make the items so central to so many builds. Also, as I mentioned, this is the return of a few runes being used for their individual effects - a lowly Nef would be socketed in a lot of endgame bows for the knockback, Ber was often used in fast attack builds for the Crushing Blow chance, and who can forget the timeless runeword IstIstIstIstIstIst, used in paired weapons by that barbarian with two Colossus Blades?
Obviously endgame content hasn’t been revealed for D4 yet, but runewords at this point should be a viable option. As in the mid game, the effects either need to be scalable through one method or another, or there need to be rare runes with better effects. Or both!
In my opinion, the ability to use two-rune runewords looks like a great early- and mid-game concept, but there needs to be more to it at higher levels. Having rare runes with better conditions and effects would be one way to do this - think of a condition rune that activates every time you make an attack/cast a spell, or once every three attacks/spells. How about an effect rune that activates one of your skills at random? It could activate one of your equipped skills, or pick randomly from your entire selection, or even specifically activate a random skill that is not currently equipped. Scalable runes would still be good, but I’m not sure if continuing to build the capacity of a shield to a bigger and bigger number would be viable or fun.
Making longer runewords really is a must in my opinion. You could have multiple conditions with one effect, multiple effects from one condition, or combinations of several condition-effect pairs. Socketable items could even have specific connections between sockets, be it linear or branching, and these connections could then affect how a runeword behaves. Imagine if Breath of the Dying could proc Poison Nova on attacks, on kills, and also when standing still, but would have less attack speed and damage when socketed in one item, and in another item it would increase your attack speed while standing still, increase damage on attack, but only cast Poison Novas on kills.
From the evidence so far, the potential is there for D4. If we can get a lot of community engagement to communicate what it is that we all love about D2 and how this could be carried forward in D4, I think the future is bright.
Well. Maybe the future is dark. And we can all embrace the darkness.