I see I didn't respond to your question.
Seems to me that there is no such thing as A perfect yard - the one you build has to fit your layout and what you want to do with it. A hump yard is for a major sorting and classification operation, receiving and sending out many trains serving many cities and industries over a large area. With several portals, this might make a layout all in its own right, with sorting and classification being the main challenge to the player.
On the other hand, if you are working with a regional, mostly rural layout, you will still need the arrival, classification, and departure parts of the yard, but probably on a small scale.
From time to time, I work on a layout with local industries and with a couple of portals, the idea being to receive through trains from one portal, take some cars off, add others, and send it out the other portal. Then, in the yard, make up consists to go out on branch lines to various industries, and assemble cars from those industries to go out with a through train or be sent to other local industries. A yard of whatever size and configuration it takes to do these things on my particular layout would be my idea right now of an ideal yard. Maybe it'll be something else tomorrow.
Dick