I also want to compare the skill wheels of Humans and Warlocks. If I find at least one discrepancy, I will replay these campaigns. Therefore, my playthrough of the 5th campaign will be temporarily suspended. I really don't want to encounter unclear bugs.
Added 5 hours 13 minutes ago
I compared the skill wheels of Humans and Warlocks. They seem to match.
They say that in 1.5, a hero with "Unveiling the Secret" can learn the spells of his spellcasting units. I haven't checked yet.
Yesterday, a very experienced player who has played all versions of Heroes (especially a lot in 3) came to visit me. He immediately wanted to try out the new Necromancer abilities. He says that in 1.5, the Necromancer is invincible. I highly doubt that. I will install 1.5 for him on the weekend.