The long list of brachos (10 psukim long), and the even longer list of klalos (29 psukim long), could be misunderstood as an indication that there are many more klalos than there are brachos. The Ibn Ezra Explains what really is going on. The brachos are given in general terms, and are therefore brief. The curses, however, are given in great detail because they're intended to scare the people into fulfilling God's will.
The Commentaries follow two major approaches regarding why the Torah lists only material brachos, such as prosperity and military victory, rather than describe the spiritual rewards that await those who serve Hakadosh Baruch Hu.
(a) The brachos and the klalos are all hidden miracles. There is no need for the Torah to state the people who engage in spiritual pursuits and serve the Ribono Shel Olam faithfully should receive spiritual rewards. It is quite natural that spiritual accomplishment should bring spiritual reward. But it is not natural that the study of Torah and the performance of Mitzvos should earn for an entire people good health, prosperity, and triumph over enemies. For example, is it natural that the observance of Shmita will enable a hundred Jews to pursue ten thousand enemies, and the violation of the Shmita laws will cause the nation to be exiled and helpless? The Torah's intention, therefore, is to teach that obedience to God is of such magnitude that it will be rewarded miraculously.
(b) Material brachos are hardly the primary reward nor are material deprivations the primary punishment; only in the world to come and in Gehenim can there be adequate reward and punishment. But someone who enjoys good health, prosperity, and security find it much easier to perform the commandments that will earn him the infinite rewards in the world to come. Therefore, God assures us that the person who serves Him with sincerity and joy will be granted all the Brachos of this world, so that he can increase his service and earn even greater reward. Conversely, one who rebels will be punished with deprivation in this world so that it will be difficult for him to perform the commandments and earn a share in the world to come.