High level Ops get EMP grenades.
Slows down hacking, HE charges, disables turrets and mines, and wipes enemy radar.
And how do Soldiers stop an objective? They can't reverse an Engineer's repairing of a primary objective by blowing it up. That would make sense, but it doesn't happen. And Medics don't get to undo anyone's work on objectives. Should they give Medics a "Suicide Pill" they can hand out to escort people that makes them automatically incapacitate themeslves?
If they were to change things (and I hope they don't), the only objective I think Operatives should counter is the HE Charge - Op vs. Soldier is more interesting than Op vs. Op - same reason so many Op and Engineer abilities interact - the two mess with one another's abilities and objectives regularly. Why not drag another class into the mix?