In war bases, when you alter a layout the time until it’s able to be used in war again is reset to 24 hours. This makes sense. It stops people copying based during war and getting practice.
However, in legends league, there is no way of getting an advantage by copying/ making a base that you have just faced/ seen recently.
I have been in legends league for a while now on and off, and just recently went to th12. Now, every time I make a modification to my bases, be it make a small tweak, or add an entirely new structure, the time on that base is reset to 24 hours. This means that all of my bases are currently not able to be used for my next defensive day in the legends league. This has caused me to automatically have to use the base that I used the last time I was in the legends league (an old th11 base) which is silly as I am now a th12 with many new structures and defences and a whole new base design....
My proposal is that the bases you can use for defences in legends league do not have a Cooldown. Removing the Cooldown will not give people an “unfair advantage” in any way like it would in war, it would simply mean you can make small changes and tweaks to your preferred and usual defensive base, without it resetting the time on that base and meaning that every time you change your base it’s allowed to take a defence the very next day regardless of how long you leave it unchanged for.