There is a long list of qualities which a good Muslim leader should possess.
Taqwa is probably the most essential and probably deserves to be at the top of the list. If I had to choose just one quality then like you I would choose taqwa.
If you have taqwa then you try to ensure that all your decisions, acts, deeds are according to the Will of Allah SWT (Shariah). You believe that you will definitely have to account for everything you do. If you have taqwa then you fear Allah and not men. You believe that true victory comes only from Allah and nothings happens without the Will of the Almighty.
Although we blame our leaders for our ills they are a reflection of us. If their taqwa is weak then that is because the taqwa in general of those whom they lead is also weak.
Regarding your comment, “THERE MUST BE NO DESIRE TO LEAD…” this is indeed true and again it comes back to taqwa. A good Muslim with taqwa will not/ should not put himself to be a leader becauae of the responsibility and accountability it entails. (However, when a good Muslim is nominated by those around him as the best man for the job he should accept it otherwise less worthy people will assume leadership.)
