The DA/MDA on the plates is based on a very simple concept. You decide to go missed, and 8 seconds later, the aircraft climbs at 2.5%. This is the basis for the 'level' section. The 8 seconds takes into account the decision and aircraft reaction time. Again, you are at flaps 30 or 40, idle descent, around 140kts...and in 8 seconds, you are telling me that the engines are spooled up, flaps are at Flaps 1, and you are climbing at 2.5%? This is what the obstacle clearance surfaces are based on.
Although certification standards require this it's usually SOP to be spooled up to approach thrust settings
"EOPs are NOT TERPS Or PANS-OPS Criteria
EOPs Do Not Provide Takeoff Data
EOPs Do Not Provide Standard ATC Departure
EOPs Are Not Developed or “Flight Checked”
EOPs Are Not Promulgated Under CFR Part 97
EOPs Are Not “Approved” By The FAA they Are “Accepted”
but again from AC -120 those contraventions are speaking about SIDS and DPs...what about approaches?...that diagram [from what I understand] shows that from the MAP a gradient 200' nm -3.3% must maintained above the obstacle clearance plane [dotted line segement? - if that is the technically correct term-but at lower gradient it's seems you'd still have clearance-to get around the obstacles...for the various engine numbers---while you don't get the full protection of an assumed 3.3% gradient. it seems the FAR 25 provisions still allow obstacle clearance-as long as WAT allows for certificated gradients?