Steep, groomed and wide: I'd go with an EC style board and EC it from top to bottom. My EC board is a Coiler Schtubby 171 with a 13m side cut.
As mentioned in other threads, EC is not necessary for steeps, but it makes the steeps easier because you're scrubbing speed with body parts. With less speed, you need less energy to hold your carve, so it's less tiring.
If it's steep and narrow or the grooming is not so good, then a slalom board is easier.