Unfortunately, because shieldwall gives a defensive bonus, it does imbalance certain units....and I know the team has spent countless hours balancing units in EB.

That being said, Ferromancer's minimod gives you the option of just porting EB to BI without adding the formations features. I would strongly recommend just using Ferromancer's minimod to port EB to BI without changing the EDU's. You won't get his slinger fix, but that can't be that hard to fix yourself (I'm uncertain of how at the moment, but I do intend to find out how and fix it myself).