The last wars our alliance has seen a lot of 1* defence teams.
The strategy behind this is simple.
By ordering every player below a certain team strength level putting up only one star heroes you make sure to minimize the points you loose.
What happens is that fair balance is lost. By doing this you fool the mtachmaking system. You get the correct opponent but make sure that your alliance lower teams will not loose what they are supposed to.
This ruins the fun in wars. One way to adress the issue would be better loot for stronger defence teams. Or ban teams below a certatin level to enter wars.
Please look into this developers since it is destroying a big part of the game, wars.