The "Return of Them" chain of updates introduced a lot of new content to the game, however a decent chunk of it revolved around a new plot line of sorts, a collection of tasks that culminated in a fight against the Celestial Champion. This "quest line" isn't the first of its kind, which was the Ancient Fuelweaver and the tools needed to summon it. These quest lines have created an issue which has been bothering me: Don't Starve Together lacks major progression in both the world and the player, despite the existence of major, overarching storylines with insanely powerful bosses.
If you don't understand what I just said, let me provide an example to both prove my point and help explain what's wrong: the weapon selection. A majority of weapons in Don't Starve Together can be obtained extremely early on. However, some of these weapons (the ham bat and dark sword) are some of the best in the game in both cost and damage, despite being obtained so early on. Once you can reliably get dark swords, that's it for weapon progression, it doesn't get better from here (thulecite club exists but who really uses that). This was perfectly fine before, back in vanilla DS, but with the introduction of stronger bosses and major plot-lines, it has become clear that stronger weapons need to be introduced as well. It baffles me that the weapons a player will use for bosses like deerclops and klaus (4,000 and 15,000 hp respectively) will likely be used on bosses like toadstool and the celestial champion (52,500 and 37,000 hp respectively). This issue applies to armor as well. While thulecite crowns and suits do exist and are objectively better than football helmets late-game, there is a certain threshold where armor is "good enough" due to the power of healing food. If you can get a bunch of blue caps, the only difference armor will make is how often you need to heal, and how much armor you need to carry around. You could use thulecite crowns for later bosses if you wanted to, but it won't realistically make much of a difference. Because of this I would much prefer new weapons than new armor, as new armor would either need to be insanely powerful or require a rework to how armor and healing works and potentially combat itself, and I doubt Klei has the balls to do that.
The other major part of DST which desperately needs progression is the world itself. As of now, the only major parts of the world that change over time (at least what i can remember) are hound waves and tree petrification. Tree petrification doesn't make the world any more challenging, it just makes wood more tedious to get. Hound waves (along with their depths worm counterparts) grow in numbers as the world progresses, which is great. However as far as I know they are the only thing that does this, and even then they could have been executed better (but that's for another day). If there are going to be major lines of progression with bosses that get more challenging the longer it goes, then the world should become more difficult too, both to challenge the player and provide incentive to travel to already-explored areas (assuming these stronger threats would have good drops).
Updates to Don't Starve Together have introduced new boss monsters that have gotten stronger and stronger each update. However, the world along with regular monsters have not gotten these boosts in power, and the player lacks any direct upgrades to combat these new stronger foes (and hypothetical stronger world that they should be fighting). I hope the next updates will resolve this issue, however as of now this is a problem, and it arguably shouldn't have been a problem ever.