None at all. IF small nation users don't matter cuz there is so few of us, then just remove us form the game alltogether. Require people to live in Italy, Spain, USA etc. and screw you to everyone else if that is how you feel about users from nations wehre BB is not popular.
Maybe we're looking at this from the wrong angle. Instead of trying to solve a "micronation" issue, what if we just got rid of nations altogether and had one big honking league structure? I suppose it would require some changes to the Cup - maybe a separate lower-level tournament, similar to how England has the FA Trophy, Football League Cup, Football League Trophy in addition to their FA Cup. Or we could allow teams to still identify themselves as being part of nations and still keep the existing national tournaments, though the thought of having some teams in a league having different opportunities for TIEing easy Cup matches as a structural issue rather than based on random matchups is problematic.
Of course, if we get rid of nations, we kill off NTs, U21 and the B3 - which is why this would never fly, though I can honestly say I wouldn't miss a one of them if they left. And it would take massive upheaval to get it set up - so I suppose this would only work for a BB 2.0 reboot type scenario. But I suppose any real solution to this is going to be a fairly significant overhaul, which may be part of the reason why nothing has been done and nothing is likely to happen.