The new mortar brings with it new challenges in base design; a lot of base designs are already designed so that not even a single wall piece goes to waste. With the new mortar, a new base needs to be made but there's no room to put it into existing bases. The problem is most acute at TH9, when there's a ton of stuff that needs to be stuffed into the core, from xbows to heroes.
Not asking for much, 5-10 new wall pieces would be sufficient, just enough to open up an existing base and make a little room for the new mortar



