Pure warfare with a staff is pointless, but hybridizing with aerothurge or another tree is effective. Use the mobility and AOE of warfare to position and get enemy armor down, and use aerothurge for stuns/blind. Unless you have spare skill slots, ignore the physical damage abilities like battle stomp
The thing about elemental resists is that while they can reduce your damage dramatically, it can also go the other way for enemies with low resists to certain elements. This means always keeping several staves handy, which is definitely tough sometimes.
No doubt magic overall seems weaker than physical, and focusing a party on physical or magic only tends to have better results. I could definitely see tactician mode punishing all magic or all physical groups though. Things like enemies with a 50%+ dodge aura, magekiller groups of enemies (lots of use of mute and high resists), enemies that are stronger the more characters are near them (to punish grouping them all up for AOE, or all melee groups) etc. All mage/all phys groups should be able to beat the game, but there should be times where their weakness can be a huge detriment.
An especially good place to do this would be with tough optional bosses that drop really good loot. For example, you could have a magekiller group that drops a really good wand. A more balanced group would be fine, but an all mage group might not be able to deal with them to get the wand.
