I only wanted Summer Cordelia. I got her after spending 9 orbs. But luck had a -Spd +Res Cordelia for me. Still not mad, I just wanted her and forget the banner until the Legendary Hero arrives.
With a +Atk -Def, I would even try to build her like her Flying counterpart: firesweep lance, heavy blade and galeforce. Even Life and Death.
Horse mobility can't compete against flyer, but in half of the maps this build can be amazing.
In Shell Lance VS Slaying it depends on the use. Shell os more player phase oriented and Slaying more roundabout/special dedicated.