Welcome to the forum.
I dropped that after taking over support, and focusing more on technical problems. It seemed a tad too cheerful for people with possibly annoying/frustrating issues, and welcoming some people and not others would have been rude.
Curse is very effective as it is, since it can be cast repeatedly on the same target.
I wouldn't be opposed to buffing Spell Shield and Aura of Guarding. I only used them mid game, though, after maxing them with purchased or found spell books. Later in the game they just were not necessary.
The bug with the scorpions was not fixed in the disk version of the game. The original GOG released contained a fix, but that was accidentally reverted with an update to fix a newly introduced bug. With the Steam release there were several issues with backups and the code changes for the GOG version were lost, requiring higher resolution support, etc, to be re-implemented. Scorpions were in so many FAQ and suggestion topics for difficult fights, etc, that they were not changed.
A 20% repair early in the game would barely bring equipment above breaking status, requiring much more frequent repairs (especially with bows).
I never used summons, but years ago in the forum (or maybe it was the old forum) a player (with a mage character) posted a defence of skills he thought unjustly maligned, including Summon Vermin, which he found to be very useful.
With invisibility and sneak, one uses mana and the other stamina.
I don't recall any other reports of maxed skills resetting to 1.
Early in the game warriors should be able to get by with chicken to restore mana, or boosts when sleeping to heal.
The game engine doesn't really support modding.