It's pretty clear that if Force Field were added to the game today it'd be all about Absorb instead of defense. Defense is already better covered by Cold Manipulation and Time, and brings little value to the late and end game. Absorb is relatively rare, and better fits the concept of a force field. Most people, myself included, absolutely loathe knockback and actively discourage its use. That leaves Force Field with AoE mez protection as its sole value. That's an excellent trick, but it's one trick.
IMO, changing Detention Field to a hold, increasing the damage to Force Bolt, lowering the animation and activation time and increasing the damage to Repulsion Bomb, and adding absorb ticks to Dispersion Bubble are the way to go.