Help me out here, and tell me if I'm missing something.
Combat sense is a Detect spell that provides +1 surprise tests and to defense tests vs ranged and melee attacks, is range Touch, and drain is F. It is a mana spell.
Deflection is a Manipulation spell that provides +1 to defense tests vs ranged attacks only, is range LOS, and drain is F-1. It is a Physical spell.
Combat sense seems the superior spell. covers a greater range of defense tests, it is a mana spell so useful for a projecting mage as well. the difference of 1 DV seems insignificant, because you are not likely to have the dice pool to need to cast higher than F4 anyway. How often do you think casting it at range would be necessary? The only two situations it seems better is for someone whose teammates often get caught in the open under fire, or for mages with specialization in Manipulation spells and a mentor that boosts manipulation.
Am I missing anything here?