My Dorling Kindersley dictionary says that the president is: head of the republic, society, college, public corporation etc. Strange, first of all I thought the church was a kingdom under the kingship of Lord Jesus Christ. The church isn't a republic, it certainly isn't a democracy, where the members have power to elect or appoint substitute 'heads' over them. The headship of Christ over the church is absolute. Looking at these things, I am amazed at how the simplest inventions of man can radically alter organic structure of Christ's body.
In the Old Testament God did appoint priests over the assembly of Israel, but sadly this doesn't justify the inclusion of presidents in the New Testament assembly.
But you are A CHOSEN RACE, A royal PRIESTHOOD, A HOLY NATION, A PEOPLE FOR God's OWN POSSESSION, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light... (1 Peter 2:9, New American Standard Bible)
When Peter said these words, he didn't address them to any appointed official but towards entire congregations (1 Peter 1.1). It is imperative that we "the called out" maintain the headship of Christ, even in our assemblies. I think Christ has enough power to preside over his congregations than any mere mortal. All we need to do is to trust him. Are you willing to trust Christ as your Presider?