Judges certainly provide legal analysis in their opinions. Like annotating, highlighting may seem unimportant if you create thorough, well-constructed briefs, but highlighting directly helps you to brief.
Do not assume there is only one issue for each legal problem.
In the personal experience on one of the authors, the sections of cases that seemed to demand the most highlighter attention were the Facts and the Analysis, while the Issues and Holdings demanded the least. Each new iteration is supposed to cure the defects of the IRAC and offer more or less freedom depending upon the format.
It is the facts that lead to the identification of the most appropriate rules, and the rules which lead to the most useful way of construing the facts.
The second category of critics of the IRAC say that it tends to lead to overwriting, and oversimplifying the complexity of proper legal analysis.
He detains person A while he interrogates him. The information included in the rules section depends heavily on the specificity of the question at hand. Because briefs are made for yourself, you may want to include other elements that expand the four elements listed above.
The court may discuss intermediate conclusions or issues, but stay focused on the main issue and conclusion which binds future courts.