Seasons ultimately reflect how poor ARPG itemization and economies are when it comes to fostering longevity. You have items constantly being created, while things of value rarely disappear. Instead of presenting players with options to sacrifice those items of rarity for gains, they instead opt to flip the game board and force everyone to start over again. This also takes stress off more consistently implementing new content, which would go a long way in curbing the stagnation of these short-lived cycles. Trade doesn’t even have to be a factor for this eventuality, but I’d argue it tends to accelerate it.
Otherwise, you can’t have early game items being end-game viable. This actually hurts the end-game because for every one of such item that occupies a slot, you’re implying the player doesn’t have to farm as much/work as hard, and thus less likely to play as long. There’s also the obvious bullseye indicating that these items are overpowered if higher level variants can’t compete. Some may try to argue that you just make these items stupid rare, but that doesn’t really solve any problems between the last paragraph and the reality that any build living or dying by such items’ presence further reflects poor itemization.
Vertical progression and tier resets are a requirement if you want to keep a game consistently fresh. And no, I’m not talking about every patch invalidating everything prior. Pacing falling more in line with expansions at 1.5-2 years is about right. Actually balance a game without seasonal resets and instead of a couple months of player finding fulfillment in a character or two, you can hope for exponentially more. Of course, you also don’t achieve this by just making everything take longer. No, you need to give people lots of ways to customize their characters, to freely experiment and not be punished for their curiosities with yet more grinding, to incrementally progress, and to present a variety of content where one build doesn’t suit all. Unfortunately, and to hearken back to my accusations of gatekeeping, we have people who try to argue that’s not what Diablo “is” and the consequence is a relatively unchanging game mired by concepts of tradition that people have either seen before or can’t maintain interest in because why play something for a year when you’ve seen it all in 2 months with other, fresher games out there to entertain. Longevity and stagnation can’t coexist.
And while randomized questing has its merits, I can’t say we’re there yet. This instead shifts the onus on better randomized maps and reasons to explore them in their entirety. To play on the purist’s take of Diablo, this also means boss runs can’t be the most profitable endeavors. If anything, I’d go as far to say that a boss encounter should be a one-time-per-character ordeal within the common setting. Their presence needs narrative significance, not significance as a loot pinata. Events stumbled upon while exploring can also help with the randomized questing angle. Some can even be less obvious like finding a key, and thus needing to find a chest within that zone it pairs to. You can tinker with treasure maps (find x spot, find loot), have collections that can unlock things or provide guaranteed unique rewards, solve puzzles (hints in the area optional), build NPC relations through accomplishing various tasks and/or giving them items, and more. If this is starting to sound like an MMO to some, that’d be because those games realized players wanted more than just killing monsters, and to keep them playing, they had to find ways to spice things up. This isn’t to say everything such games have done over the years have been good, and most of the time the major failures are a direct result of pandering to hardcore demographics that, yes, gatekeep. Still, if you’re the sort currently looking at D4 and thinking, “This looks bland/boring…” then look around to everyone claiming it should be more like D2 instead of being its own newer, better thing where you can still have depth while also being casual friendly. Because for a lot of people, D2 got boring nearly 2 decades ago and either gave it up or turned to mods to prolong its lifespan. Don’t be that hardcore demographic that tanks a game because you lack empathy for your fellow players and selfishly chase your own desires. That same 20 years between then and now has brought a lot of knowledge to gaming that shouldn’t be ignored simply because of tradition.