I do agree on the part that every ops should be doable with the standart composition. And it should be pretty easy to achieve if you tune down all the health but increase dmg dealt by droids and turrets.
However this ops is doable with the gear you get before going aswell as all fights being clearable if you know what you are doing. If you have trouble regarding healing, dps or mechanics that means youre not knowing what youre doing yet.