The first several manned spaceflight are likely to be one way trips. Too many things to go wrong plus months of exposure to cosmic rays will kill you. Not to mention the logistics of shipping enough food and water and other supplies to last close to two years.
To expand on your post, what about the trip outbound and inbound? Having three to six people cooped up in a tiny capsule is just not appealing to anyone. If I were going, I’d like to have a ship like Skylab in volume to live in. Plenty of room to live, work, and get away from the others when needed. The downside of that is there wouldn’t be enough room for the food and water required for such a long trip. Until that issue is resolved, a manned Mars trip is out of the question. Orion is fine, the Space Launch System is great, but without somewhere to live some what comfortably, you can forget about any such trip. Also, a propulsion system that would cut the travel time significantly would be an added plus.