I think my first recommendation would be to replace Champfort by Sepulcher Sentinel in CB. She's a more reliable attack down, since it's on her A1, plus her increase def / block debuffs, her passive and her defense aura. Probably in Dragon as well, for that matter. And I guess there's a good reason you're still using Warmaiden instead of Draco on Dragon, personally I would think it makes sense to swap there too? Kaiden is also not a bad champ, but unless you find yourself really needing the revives, I think I'd still prefer Sepulcher. 

On arena def, I think mostly you just have to accept the fact that you're going to lose most defense battles - logical consequence of how the arena has been shaken up by those bot teams. But for sure, any team that lacks a strong speed lead will get targeted even more. Here as well, if you have Draco surely you'd want to use him? 

Other champions in your roster who are absolutely worth building include Peydma, Lightsworn, Psylar, Alure, Zargala. Queen Eva is supposed to be an excellent campaign farmer, though I guess that's not really your priority now. 

Dracomorph!!! Book him and put in all dungeon teams and CB.

Clan boss suggestions:

Dracomorph - weaken, decrease def, poisons.

Someone with decrease attack. Fayne? But you want it with 100% uptime, it doesn't matter otherwise. Sepulcher may be better, but I don't know if she provides 100% reliably. Lose it for 1 turn - and your team dies. <- it may be wrong

Bulwark - an option to extend debuffs. Reduces speed requirements to keep debuffs on. Also HP burn.

A healer. Fang cleric? Not ideal, but I don't see other healers. I may miss some as I don't know all the champions. Drokgul for buffs and more heal? Can they together keep your team alive into 30s turns? Can one of them alone? Or give everyone Lifesteal gear and Warmaster (you should give every champ in CB team Warmaster anyway). Apo is not a healer, he's turn meter booster.

Frozen Banshee for poisons and poison sensitivity?  Prince Kymar for more poisons and resets?

No Kael, you want 5% poisons, not 2.5%.

The goal is to constantly have a boss with Decrease attack, Decrease defense, Weaken and 7x5% poisons (with optional poison sensitivity and hp burn to replace 1-2 poisons) while keeping your champions alive.

Dragon is more or less similar to CB. Coldheart is good in Dragon too if you can keep her alive. May be Kaiden, but revive should be a backup plan, not the main way of staying alive. Lifesteal gear may help on some champs.

I don't have most of these champions, so take my advice with a grain of salt.

Have you considered using Umbral in your Dragon team?