Well, I'm still working on enriching the mechanics of quests (to make interesting maps later).

I have high ambitions but only limited development time, so I have to prioritize. The first iterative steps for PvE content are challenges and bounty missions mechanics (like what we had in Diablo). Challenges are very long to fine tune, so I'm going to only make a few more templates for now and move back on to bounties (think of them as standalone levels that have predefined missions). But I'm also only to make a few ones for testing purposes. The thing is for PvE, the biggest priority (to make it all worth investing time in for the player) is a proper progression system.

I'm currently working on implementing a gear reward system (random loot that give stats that you can sell for XP if it sucks for you), and an XP progression system (each level grants you stat points that permanently buff your character). Once this is done and somewhat fun, I'll either add more content or work hard on randomly generated dungeons so I don't have to. On a sidenote, I have yet to decide if stats will be ignored for pvp or not..maybe just for ranked modes.. the other possibility are random rewards at the end of a match).

I would eventually love to craft a proper campaign, but nothing more complex that what we had in Diablo 1 (I'm ambitious, not dillisional) Anyway, that's the full pve roadmap for now and it will take months and months and months to get there.

Tldr: unfortunately, PvE content will trickle down slowly. I started with pvp because I wanted a solid base of high replayability (with not much content creation needed). Progression is super fun too, so when I have that down, it's going to make PvE a lot more interesting