Sounds interesting but doesn't work with the all modes are equal approach.
To be fair, although all the modes are almost equal, they are not actually equal and never have been.
You can exchange cargo in Open [get money for free, from generous players who have too many billions], and you can be in real danger even if you have taken no action to put you in danger, from any player who wants to take a pot shot at you [which is not true in Solo].