Leadership and Learning
By Rav Shimon Schwab
Rav Shimon Schwab answers that Yosef encompassed two great attributes, excellence in Torah and excellence in action or leadership. These traits were passed on to his two sons, with Menashe being the great politician, and Ephraim the learner. Ya'akov wanted to show Yosef that although both are important, Torah learning is favored, and, therefore, Ephraim gets the right hand. Not to diminish the importance of leadership, Ya'akov did not remove Menashe from his right side.
"This is why," says Rav Schwab, "the next pasuk (Vayechi 48:20) says, 'Vayivaracheim ... bicha yivarech Yisroel.' Ya'akov gave them a bracha in the singular, 'bicha' meaning in you, since the two of them together made up a single unit of two integral parts."