Soo I have beaten the game! It was fun to do that again after such a long time. I have to admit I used some unbalanced features which made it much easier than TW1. So here is my feedback on balance.
Some random quests give ridiculous amounts of exp. I had one quest that made me jump from level 50 to level 96 and another one made me jump from 101 to 144. You might want to rethink the randomness of quest exp.
Euphoria is broken. I really really love the new wish feature but it needs some changes. Right now you get 0.5 wishes per level. Most features other gods give you are worth between 1-5 wishes (for those that you can wish for/ comparable things). So by level 11 you basically already have one or more other gods and you just keep getting more. In the beginning I thought it needs to be reduced to maybe 0.25 but I think this needs a different approach.
This ties into the quest exp issue too. Combined with Euphoria it meant I had like 75 wish points in the game. More than enough to wish for everything I might ever need and still have points left. Also wishing for all the resistances takes like 10 wish points and if you do that you are already immune to almost everything combined with your natural restistances, found resistances and some items (right now 10 points is level 21. In level 41 you would be definitly immune to everything). I was thinking maybe make the point cost for that category go up each time you use a wish on it. (I wouldn't bind it to the restistance itself because this is kind of unfair for different races).
Also wishing for magic affinity is wayyy too cheap (I can wish for astral magic in level 6 with euphoria without any downsides like elemantalist). This is a really strong wish if you can get it early and even mid and late game it is more than solid.
So my idea right now is that you might want to bind euphorias wish points more to going down a floor than to level ups (more predictable wish amounts depending on the stage of the game). Together with lower amounts of points and more balanced prices for the strong wishes this might be good. I was also thinking about a randomness factor in the amount of wish points you get. It used to be you get a wish fullfilled or not which wasn't good but getting a random fraction of wishes seems fine to me. Than you can't plan so much in which floor you gonna have astral affinity for example (and artificially keep your level low until then).
I really love totemic whisperer. I usually restart a bit to get a good familiar (which you kind of need because it is your only real weapon). This time I hit the jackpot. I settled for Navar the elder mind flayer spirit (stranger things vibes! Maybe you should do a level with dnd and stranger things). I usually look for tanky familiars (life gain and high melee damage) and high speed but this time I went for it because it had hypnotic damge type which is soo good even though speed 2 was a bummer. Looking back I didn't really know what an amazing familiar I had there. I wasn't concious about the new ranged weapon option through weapons which reduces the speed problem tremendiously (I found a pulse rifle omg...). Everything would have been balanced ok. It would have been a strong familiar but there are several strong ones out there. But what really made this unbalanced were the spells it had (charm, mind decay, shockwave, cyclone blast and anti-magic screen). Or more specifically the increase in spell levels. The player has capped maximum spell levels but his familiar doesn't. Well in the end my familiar had a lvl 112 shockwave and apparently shockwave size increases exponantially. It had a size of 412. That meant the size of the shockwave was hitting the whole level at once. I have to admit it was fun. I descend a level unpause and the whole level dies. Just run through and collect the gold/power ups and go down again... But speaking about balance I guess this needs some work.
My suggestions would be cap the maximum spell level of all creatures. It would make the game more fun. No more out of the blue death to a random unique with level 80 great hail. Random talents can still increase the cap but at least then it is within reason.
Oh one suggestions as a side note. When you max out a spell the power ups chance is still extremely high but instead of levels you keep getting incantations. This is kind of a bummer. Maybe if the game rolls a maxed out spell just roll again until it has a spell level that isn't maxed out instead of giving incantations.
When you finally make it to the nameless one you are usually quite strong and have some allies with you. The result is an incredible light show. I was not able to see which sigil was activated in all this light. Only when the nameless one disappeared because of a bug was I able to activate the sigils. Maybe make the active sigil more obvious.
The game not saving after the usage of shrines. This makes the random shrines (or other random features like altars) save scummable.