How many times do I have to state that this is solely a rules issue?
You could make it immaterial for all I care as long as it uses charges.
But it doesnt break the rules as it is so there IS NO rule issue. Its been said that it places 1 stack of 7 Shields.
1 bone WALL card lays 7 Bone SHIELDS. Those 7 SHIELDS make up the 1 WALL, so you have to destroy all the SHIELDS before the WALL breaks down.
And it is common knowledge in card games that this is how it goes.
Rules<Cards
The cards always have more influence than the rules itself, as in card games, they are more of guidelines than rules.
. If there was a card that said your opponent loses 7 creature spaces, then that card overwrites the rule of having the normal amount. That does not mean the rule is broken, it means that there is an exception to the guideline. There is nothing wrong with that