No. If we ban NAPs, they will still exist but just become unofficial ones. And banning human alliances? It is good in warmongerish Empires of Steel but not here, because in spite of the name LKS is not really lets-kill-everyone game. However, I think that reducing a number of people in one alliance to two with an exception of countries smaller than thirty provinces is a good idea. On the other hand, as Zeit says, the number of provinces is not really good indicator as Portugal with it's fleet becomes an uber ally in later game.