I agree wih zDutchie that teammates breaking the bridge is not a big problem, but even being able to buy JUST blocks with DIAMONDS wont work, because youre forgetting one thing: this is MID.
On a map like nightmare for example, it would actually be a better idea to make it iron instead of diamonds because diamonds are so plentiful.
I think this is just a bad idea under any circumstances.
If you are stuck on mid and need blocks I personally think that's your own fault. Just be more prepared when you go to mid. After all you made the decision to go to mid without enough resources so you will have to face the consequences.
I dont really understand this.
Half of the solutions people offer to problems like these can be answered with the simple sentiment that "its your fault".
For example, everybody who wants to add enderpearls in normal because of campers can be told "You shouldnt have let them camp".
Again, I may be missing something, so I would appreciate clarification.:)