Company level leadership; fighting for our nation and preparing Soldiers. Do you agree that is everything?

With all due respect, SSG (Join to see), no, it is not that simple.

If you want to define it that simply, then the two things should be fighting for the nation and preparing for that fight.

Preparing your soldiers for that fight is only part of the latter job. There are also all the tools of the trade which need to be kept ready -- after all, what good is a rifleman with no magazines, or a tank crew with a shot-out main gun? Then there is making sure that you have at least the minimal number of soldiers you need for your part of the fight -- again, an administrative task quite distinct from training your soldiers.

Most importantly, you cannot overlook preparing yourself for your role. What good is a squad whose leader can't lead them, or a company with a commander who is overwhelmed during a battle?

Not at all, you should spend the majority of your time ensuring your reports are tip top, that every waking moment, or sleeping, your Soldier's have is under complete and utter supervision and control. Your training should be so controlled that no one ever stubs a toe. You should also ensure no tasks outside your assigned sector are ever acknowledged, and most importantly that your individual OER states the defense of this country will fail if this Soldier is not promoted tomorrow.

Oh and flu shots cancel all training if a Soldier in the brigade missed an immunization.

I'm sure there's more that can be done, but at what point do we actually pin more responsibility on our junior enlisted and junior officers. There's only so many hours in a day, leadership needs to share the responsibility. No one likes a single point of failure, share the mission, accomplish the mission, continue on to the next mission. Always training for excellence. In today's world you must train in everything and be Always Ready.

I agree with the sentiment, but I think it is much more involved than that.
Much of a Sergeant's time is (wisely) spent on getting to know their Soldiers, counseling them through their issues, and developing them to someday take on larger roles and responsibilities. As a First Sergeant, I did those things constantly, with the additional responsibility to build effective teams.
Management of our people is every bit as important as preparing them for war.

Couldn't agree more

I would add that you need to develop yourself as well. If you yourself are not properly trained and go to get more knowledge and experience how can you do anything for your subordinates? Experience is the best education and helps you to pass it down to your subordinates and peers.