In general- steers are meant to be meat- so I like to look for all of the things you need to get the best meat product possible:
feet and legs and the bone in those legs-- he has to be able get this meat to the feed bunk each day and move around
Frame- I agree you don't want a Clydesdale, but you need to look at depth and width- how much meat will fit in this calf- does he have the frame to carry it and finish it-- also you want some meat in the end so you don't want a calf that is too small.
Waste- this is important to me- what is his front end made up like-- extra neck skin, extra skin in the shoulder and brisket-- I want my steers to be clean in the front.
hope that helps and JMO