Thanks a lot for the info - and I think I know what is going on with Wind I. The rule is that if you recast it, it will always choose higher duration and higher power (so if you cast Earth II with +30% bonus and then another time with +40% bonus, the 40% will overwrite the 30%). Now because Wind I actually does negative "bonus", mathematically -13 is "higher" than -30, so it overwrites. I need to fix it so that it works with highest absolute value. Thanks - I wouldn't have caught that.
As for troll mission - I remember I went full +fire damage on artifact for this one and as for attunement, I had around lv.10 holy attunement, the rest were maybe lv.5 or 6. In general attunement should be kind of a slow grind that comes naturally, so you should not be "required" to max it in order to pass content. If it feels like that, I need to tweak it. I will test out the troll campaign again - there is always a risk that I changed something in balance after passing it.
As for artifact not really making a difference - I will look into this too, artifacts definitely should feel powerful.