Give clans a proper war ranking
To my understand the current system will calculate rank for each player based on what level of troops and building they have, and then assign a rank for the clan itself by adding up its member ranks. This sort of ranking is incomplete, because it doesn't take into account one important factor: Activity.
Victory is often determined by activity, rather than skill or strategy. Yes, one could always recruit more active players. But what happens to those who are left behind? Their fate is no different in the next clan, or the next, or the next. They are essentially denied participation in clan wars completely.
This game is filled with casual gamers. Casual gamers who can't play clan wars, because they are not active enough. SC is denying game content for many clashers due to incomplete ranking.
Rather than base it on what level of archer towers I have on my village, the ranking should be based on SUCCESS. Give clans are proper ELO ranking, which will divide the casual gamers from the hardcore. Everyone gets to play. ELO ranking is already in use in other parts of the game. Why not in clan wars as well?
More transparency in matchmaking
I have a solution for the casual players who are not fitting into CW... go join a casual clan!
What I would like to see in CW matchmaking is a more explicit/transparent ranking system. For instance, they could implement the badge system they use for trophies. Based on your base strength, attacking strength, and (maybe) CW success, you would fit into a certain badge category. i.e. Master 2.
Then you could know you will only be matched up with a clan within one badge rank of yourselves. Clans could get an idea of how they are progressing and why/when they might be receiving "unfair" matchups. Just a thought!