Madam Secretary is still fantastic after 5 seasons, and I will keep watching it.
1.) It takes complex topics (e.g. policy, in general) that normally aren't "sexy" enough to captivate plenty of people's attentions, and presents them in a simple, relatable, and even light-hearted way: the stories of Elizabeth, her family, friends, and colleagues. (After all, don't we all have family and friends?) That way, it entertains us while still presenting us with complex issues that affect our 'simpler' everyday lives.
2.) With other shows like grim-and-dark House of Cards, we need shows like MS to show us the other side of the coin - how much of the government, despite corruption in the system, is still made up of ordinary men and women who genuinely want to help make others' lives better.
3.) Never mind the right-wing nutcases who cry "hurr durr b-but liberul agenda." MS, as a series, strives to treat EVERYONE fairly, in light of facts and reason. Even if that means being too kind to right-wing nutjobs for my progressive tastes. I say they're just complaining because MS forces them - forces ALL of us - to actually think, which is something we need to do more often.
Keep up the good work!