We must not confuse approach climb gradient requirements with obstacle clearance for the missed approach procedure!
Approach climb gradient is based on one engine failed, it is similar to the climb requirement at take-off, only with approach configuration.
this requirement is, i believe, independent of what kind of approach you make. Even in a visual you have to meet this requirement. It is not an IFR thing, to my knowledge.
The missed approaches designed as per PANS OPS have a gradient for obstacle clearance (with a minimum gradient even if there is no obstacles). If you can make it with one engine out, you can fly it one engine out. If you cannot fly it with one engine out, then don't fly the approach or reduce weight, or design your own EOMAP.