Well, I did have my own concerns about the recycling of old space shuttle tech.
This is a perennial problem in the space sector. Overly optimistic assumptions are always made about the reliability and costs of using existing/old components/designs, but those components/designs were intended to be used in a particular system. Move them to a new system with different requirements, and reliability usually plummets and costs/schedule usually skyrocket.
A good example is the use of the old Space Shuttle Main Engines (SSMEs) in SLS. The SSMEs were designed to use incoming propellant (liquid hydrogen and liquid oxygen) at a certain temperature. But that temperature has changed on SLS, because the distance between the cryogenic propellant tanks and the SSMEs on SLS is different from the Shuttle. So heaters have been added to SLS between the propellant tanks and the SSMEs, and now the main propulsion system on SLS is reliant on heaters that were never present on Shuttle. That adds a new failure mode -- if a heater fails, an engine could stop working -- which drives down reliability. And it also drives up cost and schedule as those heaters are over-engineered like crazy to minimize the chance of heater failure (which will never go to zero no matter what you do).
The SSMEs were also recovered, refurbished, and reused on Shuttle. SLS will expend its SSMEs, necessitating a new SSME production line. But the old SSMEs were very labor-intensive and expensive to produce, so the new SSMEs will be manufactured using different methods and not-unsubtle changes to the SSME design to try to keep costs manageable. At that point, NASA is better off with new, clean-sheet engines and vehicles, rather than twisting itself in knots to maintain the old Shuttle workforce.
But those huge old boosters are still sitting there, and they could be used to make any sort of launch vehicle.
Again, the devil is in the details. Like the SSMEs, the Shuttle's Solid Rocket Boosters (SRBs) were recovered, refurbished, and reused. Detailed inspections were made of the recovered SRB segments to track burns and damage, prevent failures, and project future reliability. The SRBs on SLS will be expended, so many of the benefits they had in terms of reliability will be lost. Worse, the old SRBs used an asbestos liner. The new ones cannot, and there are now issues with voids appearing between the new liner and the solid rocket propellant used in the SRBs. Voids are bad -- they cause unstable combustion, which can lead to bad things in the SRBs.
As for Orion, I was never overly keen on the idea of regression to a space capsule.
It's not a matter of old versus new. It's a matter of where you're going. If you're just going up and down to Earth orbit or a space station, engineering trades often favor something with wings or a lifting surface. But if you're going farther (the Moon, near-Earth asteroids, Mars), you're better off with a capsule. Dragging the mass of those wings or lifting surfaces beyond Earth orbit (and back) is a major consumer of the limited mass available for such missions.
Even if it was going to be the Lexus of space capsules.
Orion's size is a big problem. It's an upsized Apollo capsule. That's fine structurally, but the old Apollo heat shield and launch abort system do not scale well. After trying a monolithic shield like Apollo on Orion's first flight, NASA is moving to tiles like on Shuttle but still using Apollo's Avcoat material. Unknown how that will turn out.
Similarly, a launch abort system that can lift something the size of Orion away from a launcher fireball is massive, complex, and a big drag on performance and reliability. Worse, it also has to get clear of the SRBs, which will keep on burning and thrusting even after a launch accident. More mass and complexity and less performance and reliability.
Perhaps a more aerospace specific system is under way.
There's nothing else in the US human space flight pipeline besides what the private players like SpaceX and Blue Origin are pursuing. Moreover, what NASA designs next will depend on what direction the next White House wants to go in (stick with the International Space Station and Earth orbit for the foreseeable future, go back to the Moon, try for Mars for the fourth time in three decades, focus on enabling and lower-cost technologies to support future decisions, etc.)
It's also quite possible that the next White House will do little or nothing and let SLS and Orion continue to meander. NASA is not exactly a top priority, and there are big congressional rice bowls involved that may not be worth tipping over given everything else on the next Administration's to-do list.
And I've read plenty about the military's new robotic space shuttle replacement.
Space Shuttle was both a launcher and space plane. X-37 is just a space plane. If you scaled X-37 up and stuck astronauts in it, it would still need a bigger, TBD launcher.
If you have a penchant for wings and lifting bodies, I'd say Sierra Nevada's Dreamchaser (based on the old HL-20, which itself was reverse-engineered from a Russian test-spaceplane) has a better chance of becoming a human vehicle. It's already at the right scale and recently won an award for space station cargo delivery, which will require a certain amount of human-rating right out of the gate.
There are things afoot. And as well there should be.
For better or worse, the momentum is with private efforts like SpaceX and Blue Origin. How far they get in the next decade or two will probably have a bigger impact on future human space flight than NASA's public efforts. The former is not hamstrung by congressional rice bowls like the latter.
Other nations on the rise could surpass us, which would be a travesty.
Doubtful for the foreseeable future. China's human space program is a very slow burn. They've only launched like five times in the past 13 years. Russia is a basket case. No one else has a independent government human space program on the horizon.
New frontiers being explored and conquered tend to spell doom for older, complacent powers. We need to be there, one launch device or another.
I think it remains to be seen whether human space flight ever becomes a sustainable, expanding effort regardless of nationality or private efforts. Our species' biology is fundamentally incompatible with space environments in ways that Earth's frontiers (like the New World) never were. We've spent something on the order of a half-trillion taxpayer dollars on NASA's human space flight efforts to date with very little tangible return to show for it. Apollo was an historic achievement, and everyone has a soft-spot for the Space Shuttle. But neither have left a sustainable legacy or a clear justification for continuing that level of spending.
The space cadet in me says try better. The analyst in me says dump human space flight and stick with and expand on the much more successful robotic efforts.
Obviously, my 2 cents. YMMV...