my suggestion, all the clans you can not find matches for make their clan names available, then like the old war system clans decide to challenge other clans you could not find a match for and 3 admin from challenged team have to accept. if people are happy not to war then they need not accept... no war you accept the x amount of mith but don't cripple people the chance to war because your system said no
Look, it's better to have it this way because if you're overpowered, it isn't fair to weaker clans and if you are way to weak, there's no point in warring. There is no honor in earning easy mith. Lets see how you feel when you get pairs with RCA who has 20 more members than you and the weakest one is stronger than half of your clan, how is that fair? I war to have fun, and to have a challenge. I don't war for easy mith or for impossible wins where it is just easier to ff halfway through. This system isn't perfect but it is still better than not having it because the point of a matchup system is for two even sides in power and numbers to go at it and see who wins and nothing else.
I agree that "no match-up" system should be removed. "Bad match-up" is commonly cited as a reason for defeat when in fact bad tactics, inactivity or lack of war skills are the reason.