So I'll admit I'm a little confused by why you think the senatorial class' role in die Agonie, to use the German phrase, of the Republic takes up "little focus." Popular treatments, relying on hundred-fifty-year-old scholarship and narratively-appealing Great Man may give the impression that scholarship only pays attention to Caesar and Pompey, but nothing could be further from the truth. The study of the end of the Republic involves understanding not only the actions of the Great Men, or even of groups like the senatorial class, but of entire social stations like the urban plebs and provincials, to say nothing of a host of other economic, social, and political factors. Few studies in Roman antiquity involve so many different lines of inquiry and few events involved so many people. From the very beginning of scholarship on the subject Mommsen tried to fit the senate's place in the political crises of the first century, and Syme famously declared that Cicero's piscinarii were at least as guilty as Octavian, for failing to respond to political crises and prioritizing instead the minor accolades of their own careers. I don't think I can answer this question, it's sort of asking to condense literally everything done since about 1850 or so, and a lot of people disagree or are unsure about such things--you mention for example "domestic violence," by which I assume you mean the popular political violence of the first century, a subject whose orthodox views I believe, and have tried to show in my own work, are almost all wrong. What exactly are you reading that gives this impression?