I have faced a common issue over the course of many battlefields and that is shielding to prevent an oncoming attack. In my opinion this tactic has become a downfall of this game and have made battles unbalanced.
Shielding was developed to give you the option to leave the game for a while, not to be used as a tactic to become invulnerable in battle. Last battlefield I spent hours attempting to attack a player who would break and reshield whenever we began an assault. This happen three consecutive times.
Please add a cool down or a limit to shields per use in a battlefield. It is an issue that must be addressed.