Any time I read someone saying something along the lines of "they shouldn't nerf a skill in a single player game," it always translates to the same thing to me- "I'm not good enough."
[snip]
Perhaps you should work on that faulty translator, then. Try Google Translate, even it's better than what you're claiming. 
People have different playstyles, preferences, etc. And considering the game has a casual mode "for players who prefer the story to the combat" or however it's worded, that invalidates your attempt to belittle those of us who choose to play that way and are sick of seeing things ruined in single player games to this degree. It has nothing to do with "being good enough" or not. Hell, I have a friend who's beat the game on Nightmare twice with non-mage characters but is disgusted by this change to Knight-Enchanter because she wanted to play a badass borderline-unkillable mage for rp purposes. Which, y'know, it's a roleplaying game so it's kinda what you're meant to do.
The way someone likes to play a single player game can never freaking be wrong, because their play style does not, in any way shape or form, affect how other people experience the game. Don't like how "overpowered" a spell is? Don't use it. Don't like how "overpowered" a whole specialization is? Don't freaking play as that specialization. I mean, I don't much care for the entire Blood Magic thing in earlier games, but you'll never see me whining that they should release patches years later to completely destroy that specialization on account of my distaste for how it doesn't properly fit into the game. Because it's something I can easily just not play instead of expecting or wanting Bioware to destroy the fun for those who enjoy it.