I am now in the endgame for the first time in A18 and have the impression that level gaining was better balanced in previous alphas. I acknowledge the desire of many, if not most, players from previous alphas to slow down the progression a bit, but by raising the exponential factor from 1.015 to 1.05, despite removing the low level cap of previous alphas, you effectively introduced a new level cap that is way lower than it ever was. I cannot imagine how anyone could go beyond level 100, even with the ascend cap at level 60.
I nowadays (at level around 70) get no more than barely one level per ingame day, and that only when i dig like insane with an auger. Questing or killing zombies is by far in no way leading to any noticeable level gain.
While that may be OK regarding capping of the difficulty level of horde nights (don't know if that was intended by funpimps), it well limits the fun in the endgame phase. At least for those who play the game with a fun factor in character development, that stagnation limits their fun.
Now, regarding the possibly gain-able levels, the limit of character development at beginning of the endgame phase is around 60 levels. It seems to me being a very well defined reason why you defined the ascend cap at just level 60. There is not much more the character will develop, if that cap would not have been introduced with the last update.
Even with that ascend cap, it becomes boringly slow.
With those 60 levels, you can barely max out exactly 1 of the 5 perk trees (9 perk types per attribute, 5 perk levels per perk = 45 perk points, plus 20 points in the concerning attribute = 65 points per perk tree). IF and only if you complete ignore all others. Which no one who not already knows the game from in and out would ever do. Such type of powergaming is in every existing game the endpoint of gaming for peoples that mastered the game to the roots. But it is far from having fun.
So, people playing the game for fun and not knowing the last freaking detail of optimization in advance, will likely experience a critical fun limitation.
The impression that has grown in me is: That ♥♥♥♥s. To get to a level of 130, which you would need to have the preferred perk tree somewhat maxed while having a bit of accompanying perks in other trees built up, you would have to madly auger-dig through mountains of mud for about 60 ingame days without any need of the resources, only to get those ♥♥♥♥ing learning points. Because other activities would by far not yield a fraction of the necessary XP.
Summing this up, i recommend lowering the exponential factor again, to something higher than in alphas until 17, but rather lower than that of A18. I for myself modded that exponential factor to something like 1.02 in the previous alphas and was satisfied. In the current perk scaling however, it maybe would best fit to set it at 1.03 - remarkably lower progression than in previous alphas, thus effectively limiting the level at around 100-150 (depending on the penetrance of the player), but sufficiently quicker and more prolonged progression than in the current state. The same time i would scrap the ascend cap.
So for my next playthrough, i will modd it that way and see if it's more satisfying than at the moment.