Man-rating & ARV
Apart from Gs, vibration, noise, temperature and breathable atmosphere, there is a major change in design philosophy when something is man-rated.
Generally speaking, for "reliable" stuff, you assume that everything must work after a single failure, and that failure can be anything. If something is really super-critical, or if there is risk of significant damage or human harm (e.g. a rocket taking out an entire launch complex), then you have to assume that you can have any failure, and any other un-related failure at the same time, and it will still be "safe"; It can fail, it can blow-up maybe, but won't destroy everything and kill everybody.
Now, when you have spam-in-a-can, you have to assume that for any two completely unrelated failures, everything will still carry on working no problems. Even in the event of a catastrophic failure, everything has to hold together and keep going straight for at least long enough for any escape system to operate and get the spam clear of the fireball that the launch system turns into.
That takes a lot of work upfront working out system architectures and overall designs, then later it takes an astranomical amount of work proving out that two entirely independant failures aren't a problem. Certainly some of the control systems of Arianne were designed with that in mind.
As for ARV, I thought that there was a plan for another run at ARV launched from the new VEGA rocket. The plan is still that ARV is for returning experiments from space rather than people, but maybe that is just s step on the way.