I have played through to the current end game once, and am making my way with a new player that's a friend of mine.
The issue with progression in our collective opinions, is that it's relatively disappointing to get frontiersman gear which can be taken all the way into the current endgame, in a level twenty zone.
We got it in our very first antiquarium realm, and it immediately got us all over gs 60. The quests on the side panel then jumped forward, and skipped to the herbarium card quest. So you lose all guidance and suggestion to visit other realms of a specific type.
The secondary part to this issue, is all of the crafting components we have is meaningless when it takes a lot of time to find the crafting recipes, and then get the augments build, but you already have 70+ level gear. It makes every bit of the other crafting recipes you get irrelevant because you don't need them, and they only go to level 41. I've tried for reference, replacing all of the pieces for these gear items with tier 3-4 materials, special mats collected from mobs, and no matter what I did even using the cards, could not get a high enough level to justify using those lower level items because of one set I got at level 20, that has a gs of 70+ with crude materials.
I strongly feel that much of the quests, and the items you can get, are not being utilized well by the game itself, as why collect useless gear that's just going to sit in chests, when my item count per server is so low? I don't have enough room to have chests full of collectables that aren't useful past low end content, and I don't even have any dummies to put the gear on for asthetical purposes.
All in all, I strongly feel there needs to be more reason for the lower tiered gear. I will also say, if you settle on a lower tier abeyance realm, the boss fights to get realm cards are trivial, you can easily one or two shot them at higher levels, so even progressing through the realms does not feel very impactful with the boss fights being the same level as other easy moves in the realm. It would be nice to see them scale with your gearscore, or be in other realms at harder difficulties to feel more like an upwards progression system.
All in all, I feel strongly that the quests should not be skipping just because your gs got so high, I do not feel that gs 70+ items should be available in a level 20 zone, the boss fights and quests are easily done or overlooked and therefore the progression in those areas does not feel as rewarding, and lastly relating to progression, I strongly feel that where crafting and all of the item bloat is concerned, it feels bad to get augmentation stations, with zero hint that you need the recipe cards on top of that. It leads to disappointment, and a feeling that the progression you've made, isn't real. It also again, feels terrible when you finally get the recipes and some of them are locked to level 41 or so, even with high tier ingredients, because a lot of times you already have that level 70 gear and have no need for level 40 something base gear. It'd be nice to see things tweaked in such a way that provides better information on how the system works, as well as seeing the crafting balanced for a better progression system.
As of now for quest progression, the quests don't feel very meaningful or impactful, even though I'd love to see the story shine more, so quest progression doesn't feel necessary.
Progression in general feels a bit all over the place in every area so far that I've experienced.
It does suck as well, that the lower tier guns are so low in impact compared to just your average non weapon tools. You finally make a level 20 set of tools, and you get your first blunderbuss... It's level 16. And it hits a bit like a wet noodle compared to other level 16 tools, let alone level 20 that you've finally made! Especially for how close you have to be to hit at all.
I love the sandbox aspect, but knowing the progression is there, and feels a disoriented, is definitely a disappointing aspect to run into. Especially with how intriguing the story is, and all the characters based on historical figures, it has so much to offer and I'd love to see more stability and consistency in progressing through the game in all of its unique aspects.
