According to Catholicism, why did God create men as men rather than as angels? There is some discussion about why God created man here. The answers go something like "God wanted to love us, share his perfection/happiness/life with us. Therefore, he created us." 

Yet, God also created angels. Beside some fallen angels, most of them are in Heaven, already enjoying the beatific vision of God face to face. There was no salvation process involved. No sin. No pain. These are spirits (i.e. bodyless souls) created to be happy.

So, the question is, why did God create souls in the form of men, rather than creating these souls in the form of angels? The answers to the linked question do not address this issue.

The context of this question relates to the problem of evil. God sharing his life with us whilst respecting our freedom is a "classic" answer to the problem. However, this still begs the question of why God created man as man rather than as angel.

PS: there is a related question here but it is not denomination specific, and the answer does not really answer the question, imo.
Although not a magisterial teaching, Padre Pio said:


  The angels envy us for one thing only: they cannot suffer for God.


cited in Padre Pio: A Catholic Priest Who Worked Miracles and Bore the Wounds of Jesus on His Body p. 31, from in Fr. Alessio Parente, Send Me Your Guardian Angel, National Centre for Padre Pio, Barto, PA. p. 65.

Thus, it seems God created man a body+soul composite and not a pure angelic spirit in order that we may love and suffer for Him in a way that angels cannot.