After having spent roughly 150+ hours in the endgame (recently), I've considered a few options that would drastically improve the replayability and (more importantly) enjoyment.

Firstly, if I can draw inspiration from other titles in the genre, I'd like to start with a relatively smaller, and seemingly unknown game called, "Last Epoch."

In terms of endgame mechanics, Last Epoch has two "modes" that are both considerably more interesting than how expeditions are presented in Wolcen.

The first one being "Monolith," which is basically like an improved version of what expeditions are, so ideally, using similar ideas to bolster what can be done within expeditions should be considered.

Then, there's the arena. This one seems self-explanatory, because I've seen examples of this concept in numerous titles, not just Last Epoch. However, Wolcen would greatly benefit from this concept, because it offers immense replayability by infinitely scaling enemy difficulty in a "horde-like" game mode. Enemies become stronger, higher waves require more patience and calculated gameplay decisions, etc.
The best part of this game mode (aside from the improved loot acquisition) is that EXP also scales up with each series of waves. Wolcen desperately needs an EXP multiplier that allows for "power-leveling" within a reasonable amount of time, especially when compared to how unrealistic achieving the current level cap of 90 is in Wolcen.

The reason we need more diversity in the endgame through the implementation of GAME MODES is because NOT EVERYONE (even in your core audience) wants to participate in a "seasonal reset" or a league(s) system. This concept has been recycled numerous times in other games, but only maintains a fraction of the playerbase; as completing mundane tasks like replaying the campaign over-and-over again is less than ideal. This should NOT be the only way to start leveling/gearing for a new league. This is where most games in this genre fail. Other endgame activities should be accessible in order to reduce the inevitable "content fatigue" while leveling a new character for a reset. Mind you, that's IF you decide to implement a proper league with online ladders and whatnot.

To my original point, by introducing OTHER endgame variety would be more interesting than simply resetting with every new season. With respect, Path of Exile has a metaphorical stranglehold on that marketshare, and rest assured, I don't foresee your implementation of seasons even remotely competing with what Path of Exile currently offers. I'm all for competition, but I believe that your efforts should be focused on other potential endgame systems.

Perhaps the ability to replay campaign missions, with level scaling, or even a modifier option. Heck, even a difficulty selection from a mission-overview screen would be nice. Frankly, Wolcen Studios developed one of the most unique and memorable storylines in recent memory (when compared to their competition). These assets likely required a lot of time and dedication; why not make them accessible again, but with endgame modifiers.

Another idea would be creating some kind of a "boss rush" mode; allowing those story-based assets to be combined with expedition bosses in an arena. Basically, take what you've done with the "Uber Boss" concept and build upon that as a standalone mode; straight to the bosses, without the need for specific items to experience this as an endgame activity.

Of course, these ideas all seem like common sense or rather straightforward, but I have others. For now, I'll spare those.

I realize that new content seems to be what the masses are waiting for, and I applaud your efforts to appease them... but I certainly hope that bug-fixing, further optimization, and re-balancing (not merely nerfing) are going to be a massive priority. The foundation of this game is fantastic; a lot of potential. But honestly, the little issues with inconsistent frame-timing and other performance-related hiccups are troubling, and no amount of new content will be a sufficient band-aid to improve the overall experience.

Regardless, I'm eager to see what Wolcen Studios has in-store for us, but I'm cautiously optimistic (like most people are).

Thanks for coming to my TEDTalk.