So while the impacts are different it DOES impact both sides in a potentially negative way.
How so? I am yet to be honestly convinced that it ever will. Sure, there would be a trade-off's for switching groups which people going from all/all to private to single player will have to deal with.
Private:
Limited to the people you know on yours friends list, this will and can vary. After listening to the Lavecon broadcast we're probably currently limited to 16 people per instance and anyone whose connection speed is too far off will likely have a hard time playing with these friends. Due to the size of the core systems, most of what we'll be encountering will be NPC's anyway, so any large group of friends in all/all will likely still dominate.
Solo:
Benefits of only seeing NPC's, slower to advance because you cannot co-op with other players for those particularly big runs and even with two wingmen they won't be as effective or as good as a co-ordinated PC group. Progress will be slowest of all the modes.
Potential negative side to forcing a group:
Future play may involve the necessity of actually switching to full modes, such as multi-crewed ships and for those in single play mode will then be forced to start again.
I have had to rush this, anyone else actually got positives and negatives? I really want to know why Frontier should limit the choice to that one time only at creation, without any possibility to switch.