Many idealistic Bney Torah leave the walls of the Bais Medrash to involve themselves in tzorchei tzibbur. While this is certainly meritorious, it is important to note that the highest form of tzorchei tzibbur is to remain in the Bais Medrash and climb the ladder of Torah greatness by devoting years and years to intense study.
One of K'lal Yisroel's greatest needs today are poskim -- scholars equipped with the broad-based knowledge of practical halacha to deal with the myriad questions that arise in all aspects of Jewish life. We do not have the halachic giants of past generations who were fluent in the four sections of the Shulchan Aruch and its commentaries. Additionally, the extremely complex shailos that arise due to the advances in science, technology, and medicine makes the need for poskim that much greater. Virtually none of these contemporary questions are explicitly dealt with in the Shulchan Aruch or the responsa of the past.
A scholar has the ability to zero in on the root of the issue and its halachic ramifications. He can find precedents to the current dilemmas and can arrive at a decision based on the opinions of Torah giants of a previous era. However, the skills to do this are not acquired overnight. There are no shortcuts. They require strenuous efforts and an all-encompassing dedication to the task at hand. Combined with a great deal of siyata d'Shmaya, this diligence can produce the Gedoley Yisroel that K'lal Yisroel so desperately needs.
Source: Sefer Darchei Noam, based on the teachings of HaRav Avraham Pam, zt"l