You should add this to the wishlist stickie.  

I have so many champs it takes multiple screen shots to show them all.  

I have to agree with this. I'm in a high ranking clan (well, less than 1000 any ways...) and our min power requirement is 10 mil. Some of our guild mates are between 10-15 mil but have issues doing NM or UNM CB, Hydra, and/or Chimera. We do have a discord server but it would be very nice to see their champs in clan.

Although, I would maybe put a 7+ day requirement to be able to do it. It's rare but when you're less than 30 members, we've had the other clan in CvC/Seige/ and sometimes bosses take an alt into our clan to try to peek at how much power a member has.

I think that would be a good balance to it.

You can already see their public self-card by clicking their name in the stronghold/post/tower and seeing acct size plus fave champs.  I do it before pointing out opportunities to fellow clan mates in the middle of Siege.  Why would joining an alt matter other than to spy out the Discord chat?

because you could see defense teams set that you havent reached yet, and know which champs to save for specific fights

Oh, yeah, that. 😜. Dirty rotten scoundrels.

Cheaters gonna cheat.