I think up to Osiris the progression methods in game are ok. There are enough dailies to keep you going and solo-grind is still a possible option.
Once you hit DWL/DWU, you literally hit a wall. DWL I'm on the fence with because some of the mobs have elements, but the others that dont hit so hard it's near impossible to solo or tank more than one at a time, even if they are in your level range. The first 3-5 levels post-Osiris are really rough, especially if you do not have +20 gears or a self heal/heal pet that actually can maintain your hp through the monsters high dps. I was ok on my soulmaker with osi set because of runes and cure. If i did not have cure I could not manage there. My ranger is stuck at ml24 due to this. I have willow worker pet but even with max pet cd, I still can't kill more than one at a time, and even then sometimes it's cutting it too close. What is really weird is the dps difference between DWL and DWU. I'm unsure why DWL seems to be harder than DWU. I could clear the skull mage daily on both SM and Ranger with no problems at ML 21+ but doing DWL skel minors quest I almost always died everytime trying to run back to the npc to turn them in.
If it were up to me, I would add elements to all the mobs in dwl/dwu and if possible tweak their dps a bit. It seems offbalance to only be able to tank more than 2 of dw mobs once you hit eddga gears or higher, at which point you dont even get exp from them(speaking from a non-refined gear standpoint).
I would also add that skeleton archers need a range tweak I think. Either that or the mob distrubution on the map changed around. That is one of my other issues with DWU in particular. If you are trying to get to LR to do DWU LR grind, most of the times, trying to get there will result in death if you: a) have no cure b.) have low/soft(cloth) gear/low hp pool c) dont have ymir+guardian fully charged + move speed potions d) dont have stealth e) don't have a mount with movement speed boost option. This seems a bit overkill to just walk to a grind location. You should be able to walk around mobs that are in your level range and not die in 3 hits.
Additionally, I think more dailies in either dwl/dwu could help the stagnation of that area. When I was ml 26+ I was doing DWL/DWU dailies along with Morroc Board and MF dailies and even then, it was only around 8k mp a day. Trying to level purely off those because solo grind was impossible took a REALLLY long time.
Now that I am in FP lvl range I am facing the same issues as in DWU. Just trying to reach the tiger grind location is impossible if I dont have ymir+guardian+ speed pots up. If I was not a cure class, I wouldn't be able to make it at all and even being a cure class, if a single mob hits me once and crits, I die from 30k+ damage. This is with going full VIT stats. My only guess is that I either have the wrong runes/seeds/hones or it is because I do not have +20 set. I feel like the hones/seeds might be a valid point because the eddga set loses almost all seeds except one, which means I lost all my blue seeds which helped my hp in DWU and lower levels.
Regardless, I cannot solo in FP. Even as a cure class. Even with vip + priest buff + all my links and full cure stacks, the mobs hit me for around 15k dmg (my hp pool with all above buffs is only around 30k). I die in 2-3 hits or 1 crit. This has pretty much killed my leveling progress. My only options for leveling are JDQ which are extremely selective about who they let in and also few and far between, or dailies. The exp I get from DWU/DWL, Morroc Board, and MF dailies is poop compared to the amounts I need to level at this range. I cannot do any of the jawaii board dailies solo. ALL the monsters in Jawaii one shot me.
I'm unsure how to even tweak this difficulty at this point. The game was bearable through Osiris grind but with DW difficulty, FP and now Jawaii, it kind of feels like either I am missing something and that is what is making this grind in these areas impossible, or the game difficulty scale spikes really hard from DW onwards.