The separation velocity they chose for the first stage is very promising. Given the cheap cost of fuel and difficulty of making the 2nd stage body able to surv

The separation velocity they chose for the first stage is very promising. Given the cheap cost of fuel and difficulty of making the 2nd stage body able to survive the much-higher re-entry velocity, I wonder about separating just the engine package and essentially hiding it in a typical capsule shaped cover. In any case, staging based on reducing overall cost and difficulty of recovery are pretty cool. I'm willing to bet money on ceramic-ceramic composites adding enough re-entry options (in addition to lighter nozzles) that the staging is changed yet again.