Of the ones presented, the current CEV is the best...but...
NASA is repeating all of the same mistakes that they did with Apollo, Shuttle, and Station, but managed to avoid with Mercury, Gemini, and Skylab. Essentially, internal elements of NASA compete with each other, and their support of mission concepts ebbs and flows with how much it benefits their own team or center, and are rarely about technical issues.
With Apollo, Shuttle, Station, and Orion, NASA went to private industry with an RFP (Request For Proposals) and each of them would draw up their best ideas. By the time this RFP would go out in each case, NASA already had its own ideas. Each time, NASA rejected the potential contractors and went with their own ideas. These occasions were called:
- Apollo (Phase A)?
- Shuttle Phase A; Alternative Space Shuttle Concepts (ASSC); Low Cost Shuttle Surrogate Booster (LCSSB)
- Space Station Phase A (which ultimately dragged through several iterations from 1982 through 1993.)
- Crew Exploration Vehicle Phase A
In the case of Apollo, the contractors had no impact at all on the NASA concept, which got adopted. The General Electric "D2" was the most intriguing...Soyuz is almost identical!
For Shuttle, they got their heads handed to them by OMB, which was probably fortunate. The front runner into Phase B was technically of very high risk, and probably impossible to actually build. Of course, failure of Shuttle back in the seventies might have put LCSSB concepts on the front burner, and we'd be in much better shape today; God only knows. The contractor which had the most impact on NASA's thinking was Grumman. North American Rockwell was selected as the contractor anyway. I've noticed several decision points during the development of Shuttle, where NASA selected the worst of several alternatives (on at least one occasion, the contractor for the second worst alternative sued NASA for bias.)
For the Space Station, the contractors had a number of wildly varying ideas, none of which particularly stood out as cheaper or better. None of them resembled the current station. That was Phase A. For Phase B, after NASA selected the "power tower" configuration, the contractors submissions were all identical to the NASA configuration...so much so that the only way to tell them apart was by looking for the logos. I wonder where they got that from? Again NASA got their head handed to them because the power tower configuration was inappropriate for microgravity research. Over the next eleven years, and $8 billion (various years' dollars) the waystation function was castrated out as OMV and OTV space tugs were cancelled and the sucker was reduced to a microgravity research station. The most practical way to launch such a station is with one shot, as building stuff on the ground is easier than building it in space. That option was formally presented in 1993 and promptly rejected. The driver for every other design of the space station after Phase A was to provide the Shuttle with a manifest worthy of its capabilities, and is why Option C was rejected.
Crew Exploration Vehicle...(Funeral March, Darth Vader or Sephiroth theme optional)...
Phase A just happened, with none of the contractors (including selected Lockheed Martin) having any influence whatsoever on the NASA baseline concept, which was selected to provide a payload for Ares I, an otherwise useless booster. Both Boeing and Lockheed Martin hammered on NASA's door offering enhanced EELV options (Delta IV and Atlas V, respectively) as alternatives to Shuttle-derived boosters, while ATK (the growing company that absorbed Thiokol and more recently PSI) similarly advocated Shuttle derived stuff...even though it still builds solid motors for both EELVs. Of course, SDV stuff is owned by Marshall Space Center, which apparently had the "deciding vote." Of the Ares vehicles, the so called Ares V (named based on the final Saturn convention, which had Saturn II, III, and IV...just they never left the drawing board) is essential. There are better ways to do it (primarily trade in the solids in favor of a low cost reusable liquid fuelled replacement), but the capability is essential. The Ares I barely edges out the heaviest current EELV's, which can tweak up the performance needed (or better still, grab one of the lighter, more practical CEV alternatives.)
Contractor slighting factors: