Let containment work for teammates vs. AV and GM class enemies. If the AV is held, stunned, or slept, they take double damage from everyone. Immob would probably be broken. This would primarily benefit troopers and doms. Another option would be for the mez to suppress defensive toggles, but that would probably be hard to implement in a meaningful way.
This would give teams facing DPS checks a ranged alternative to blasters and corrs.