My guess is that with so many tweaks to content they didn't want to be too heavy handed with nerfs/buffs until they get a good sample size of feedback. Our group intends to do a big review after 3-4 playthroughs. We are looking forward to working the summoner into our ideal setups in some capacity and maybe a tiny bit more emphasis on necro for mosquitos and infect.
Last comment - I still feel experience is way too high and it stops us from enjoying more of the game because we constantly feel compelled to skip content in order to keep our levels reasonable and preserve the challenge. We've left the 2nd island at level 18 before and it is just silly. This never feels good and I think about a 20% reduction in exp across the board (starting at 2nd island) would be very warranted. The first island is perfect though - we do absolutely everything and still don't feel overleveled. Just our opinion!
I think that reducing experience gained after level ~10ish would make the game harder and, in my opinion, more fun by default.
However, i'm quite sure that the reason for this not being the case already is due to many of the quests being optional. This in turn would most likely cause issues for some players that are only interested in the main story arc and/or do little of the side activities, resulting in those players being under-leveled, thus creating a less than ideal scenario for both the player(s) in question and Larian Studios. (Which would end up dealing with criticism)
When it comes to the rebalancing of certain spells; I'm not really concerned about most RAW Damage output abilities, with the exception of those mentioned by Larian themselfs, ofcourse. Most of the vastly overpowered spells are based on their utility. such as; Living on the Edge, Death Wish, Spider Form, Wings, Invisibility, Haste, Skin Graft, Etc. Each skill on their own is not that big of a deal, untill you decide to fully buff one of your characters, use Flight and/or Invisibility to the High Ground and simply wait for the opportune moment. By making some of these abilities personal you could restrict the player of doing so. However, i wouldn't want to be limited in this manner simply because there are no alternatives nor content that lend themselves to this level of min-maxing.
In the end, i would need to play trough the game again in order to make a proper final judgement, in terms of overall satisfaction and sense of challenge, provided by the changes made to the game. Besides, if this is not going to be the case then, we can always try to tailor the experience in our favor, with the use of mods.