You do not need to complete the battlefields. Monsters being outside of the play area in the BF does not have much of an impact on the game, so may not have a high priority to fix. Perhaps the fix is more involved, or something else has to be updated first.
You can unlearn Sharpen, then learn it again at a lower level, to keep the required agility within reach of your characters.
I believe if someone does a job that job should be done right. The BF was put in the game to enjoy and be part of the game. I should look forward to playing the BF. I don't as it is now.
I understand I can unlearn a skill but when I do it should be my choice to do so, not be forced to do so because of a lame patch. This isn't a Multi play game where skills affect others. This was just a bad choice of a skill being nerfed. We do have difficulty levels we can play in this game. I think sharpening could have been changed in a more constructive manner is all I am trying to say about this skill.
This is only my opinion and how this affects me.