What and Why:
I've been thinking, And I think it'd be really helpful to have camps separate from my normal camps that can only be used for clan wars. In doing this, I'd then be able to go along and raid like normally. Now, If I made troops on preparation day specifically to attack an opponent, I may have to wait 18 hours before I can attack somebody again in multi-player because I'm saving my current troops to attack in war.
How:
Maybe in clan wars, you could click on your base and there be an option that says, "War troops" and your normal barrack screen pops up and you just choose what troops you want. (similar to the edit war base option) Or
maybe you can buy a war camp in your regular base. You can compact it by making it a square (like the hero's platform) and then from there, have the "edit war troops" option Or
***My Favorite***Maybe just click on the barracks and there be an option for war troops, and for the moment being, the barracks and army camps glow red or something and clear out. From there you would go through picking troops as normal, they would just come out onto the War camp. then there could be a button that says "done" and the screen goes back to normal, the war troops disappear and the normal troops appear back on the camp. But really your war troops are saved. [if you click done before they are finished training then maybe they come out of the barracks as ghosts and disappear when they get to the army camp] Then when going to attack in a war, there could be an option button that says, "attack with: Army or War Troops" (something along those lines) and you use whichever set you want.
Again, I know it'd be difficult to get running smoothly, BUT IF IT COULD GET DONE, that'd be amazing.