Here are my initial impressions after levelling two characters into the 90s/low corruption empowered content.
Regarding leveling and levels
In general the progression feels very linear both in terms of power and enemies which I really like. In general I find leveling to be in a good place. I would have expected (but not necessarily liked) a faster progression from 65 to 85, but I am probably biased from PoE where 65 to 85 can be done extremely fast. I think the 90+ leveling progression is a tad fast compared to how long time it takes to farm the monoliths. I did not expect to be at 96 and still be needing to upgrade most of my blessings. I will for sure hit 100 long before I have the blessings that I want for my characters. Maybe that is a good thing I don’t know. Again I am probably biased from PoE where going for 100 is a monumental task where your build will be complete long before hitting 100.
I find the level rewards (passives) at higher levels to be slightly underwhelming but I actually think that is a good thing as it makes it easier to increase (or even remove!) the level cap in the future without power level going through the roof.
Regarding monoliths
The only point where I experienced a rather large jump in difficulty was going from non-empowered to empowered monoliths.
This is not unexpected as we go from lvl 90 to lvl 100 with a 50% more HP+dmg modifier as a baseline.
I do not think that a jump in difficulty is per se bad but here I do not find it ideal. If there was other things to do in between it would not feel terrible, but as it is, it does not feel good to rerun regular monoliths knowing that you are looking to overwrite that blessing you get at the end with an empowered version as soon your character can handle it.
Speaking of blessings; I find them to be a bit too strong. The difference between having four usable blessings and having four mediocre ones is light and day.
One suggestion that comes to mind to remedy both would be to change the power of a non-empowered blessing to be 1/3 of the power of the current empowered equivalent. Then as a reward for completing an empowered monolith you unlock a second blessing slot for that timeline. Thus when you have completed both monoliths in a timeline you end up with two blessings of 1/3 of the current empowered power level.
This would give players the option to farm their favorite (first) blessings in regular monoliths before they take on the empowered content without feeling they are wasting their time.
Regarding items
I really like the progression that the crafting system enables. It actually makes sense to try to craft small upgrades all along instead of saving all your wealth until the very end. This is a major achievement! Kudos!
I also like that the item philosophy/crafting system makes regular items into chase items. I am sure everyone here dreams of dropping a BIS T7 mod with some good side mods on the optimal base. And getting that kind of item for every slot for a character will take a long long time (as it should). At least in a non-trading or SSF environment. In a trading environment I would worry that the market would quite quickly be flooded with such items and thus nullify the chase. This is the main risk I see with the game at the moment. If you easily can pick up any T7 from the bazaar then there is really not much more to do in the game. If trading becomes as accessible as it is in PoE I would not be surprised if you could comfortable completely outfit a character with BIS items within a three month cycle.
A slight grieve I have with the crafting system is that it is by construction very one dimensional. All usable items are either shatter fodder or crafting bases and you interact with the them monotonous manner. I miss the intricacies from legacy PoE Harvest where you had to combine many different steps; finding the correct (influenced) bases. Creating blue items with hard-to-get mods. Smashing them together with awakening orbs. Then figuring out the best path to obtain the final outcome you want through meta- and harvest crafting. Here you just shatter and hope or slam and hope then rinse and repeat. I am not (not at all) advocating that BIS items should be as easy to get as they are in PoE (even now) but if the process towards creating such items could be made more interesting I think it would be a big plus.
Regarding resistances/penetration
This is one of my pet peeves so bear with my rant here.
I get the idea behind the 1% of penetration per level up to the res cap of 75% to offset the increasing rate of return on resistances. I find it a bit arbitrary though, why 75% and why stop at level 75. To me it feels like a band-aid solution to the real issue which is that 75% is a bad level for maximum resists to start with. Just because some ARPG in the past had a 75% res cap it is not set in stone that any ARPG must have a res cap of 75%. PoE fell into the same trap and still suffers from it ten years later.
I would rather lower the res cap to, e.g. 50%, and the remove the penetration and balance mods and monster damage accordingly. This gives more design space to have mechanics that either penetrates player resistances or increase maximum player resistances without incurring as large scaling issues as a higher res cap entails.