Your suggestion is a bit confusing. You say it should be open only, or solo should be excluded, but what about group? Your main reason for open only/no solo seems to be "because its multiplayer", which group also is about so surley it should not be open only but open and group?
Alltough I cant really agree all that much, Powerplay has been designed to work with solo and all the mechanics have been designed to work without getting into the same instance with your Enemy and/or Allies. No Powerplay mechanic even incudes PvP.
We keep saying in but some how it keeps failing to sink in.