The only way this could be even *considered* is to allow the attack to happen only between players who are within let's say 10% military points of each other (not counting defense). This is the only way to prevent bullying. Whale accounts could destroy whoever they wanted otherwise.
Even like this however, without the security of building something permanent in the game, manly players would quit.
but it also creates a chance to acs defend ninja someone whale accounts generally arnt all friends and it creates a chance to hurt them.
I by far am not a whale account im rank 500s in my uni im just trying to think of things to make the game more exciting