Skyrim – walkthrough and progression.

You're probably right, but if the level scale relative to skills isn't linear there (although I haven't noticed any major non-linearities), then it might not be the case.

It's actually quite non-linear. As far as I understand, the current level of the jackal depends on the ratio of the level of the raised skill to the current level of the hero. The first 5 levels progress very quickly, and then the level scale is significantly filled only by the most developed skills of the character.

Yes, the Archmage's quarters are something special, but there's no forge for complete happiness. I also have a house in Whiterun and Solitude, and I haven't bought any more. I must say that the Whiterun house is quite nice, and the Solitude house, although significantly more expensive, is quite spartan inside.

The only thing I don't like about the Solitude house is that it doesn't have a forge for that price. It just doesn't feel right.

Added 1 minute ago
I'll conduct an experiment with changing and restoring today, as I have the spells.