The reason that Prophets are held in such high regard is because they are the demonstration of Allah's commands/word/criteria put into action. The prophets (peace be upon them all) were chosen by God to lead and guide a society that needed guidance. All the Prophets that have lived on earth were given that task for their specific times, in their specific lands, with the people they lived amongst. No matter how many prophets were sent and chosen by God (and Muslims believe that since the dawn of human living their have been close to 125,000) they all had a unified duty and cause--To demonstrate the proper way of conduct and living based on God's commands and criteria.
Let me put it this way, God could bring down commandments, signs and revelations all He wants but most people would ask for a visual aid or example to follow. A prophet would fulfill that need. The Children of Israel were guided by Moses (pbuh) to follow commandments and criteria revealed by God to Moses (pbuh). Christians believe that Jesus(pbuh) was God's word put into flesh. Now barring the whole mess of the Trinity, the question of divinity or not, this is basically the prime example of the importance of Prophets and applies to all of them. They are God's word exemplified.
The Prophets were people that God could just point at and be like: "That's what I'm talking about!", "That's how you should act/behave" "Just do like he does and you'll be rewarded". The prophets are
examples of proper human conduct, with the main Prophet being The Prophet Muhammad(pbuh) because he was the last of the prophets and was elevated by God over the rest of the Prophets that had come before because he exhibited all the qualities and characteristics of an ideal human being.
Hope that helped.