I am not sure if this has been suggested before, but here is the basic idea- Similar to Leader, elders, cos and members, I suggest one more category called Viewers.

Short version-
Viewers can see war attacks and chat in clan chat, they don't count as members. Viewers can't donate or request.

Long version-
I am a clan war enthusiast, and I often feel that some of the best attacks are often viewed by only a handful of people unless it's uploaded to YouTube. Everyday in coc, there are thousands of wars going on, and for each war, only the 2 clans competing can view the attacks. I feel that Supercell has balanced this game so beautifully, hence attacking is an art and great attacks deserve good viewership.
So, my suggestion is, let there be a category called "Viewers". Viewers of a clan can't see traps on battle day. Viewers can't see the war bases on prep day, they can only see the current village base. Viewers can't donate to requests. Viewers can't request for troops. What Viewers can do is they can see the war attacks, and can chat in clan chat. The best part is, a viewer doesn't count as a member, so a clan with 50 members can have Viewers as well. There is no limit to the number of Viewers a clan can have. I think this would be a boon for clans which have max number of members but still want some of their friends from other clans to hop in for awhile just for a chat.
A viewer joining a clan is similar to how a member joins. A separate clan setting allows the leader and co to change Viewership settings as "anyone can view", "invite only", and "closed". For a player to join as a viewer to a clan, he has to be clanless.
I feel this would greatly improve interaction between players and clans and the clash community in general. I honestly see no downside to it, and I feel it wouldn't need much time or developmental work to implement this.

Please give your comments, suggestions and any loopholes or clarifications below, thanks.