I hear what you're saying
blip and, apart from being a procedure designer, I'm also a pilot so I've confronted all of the same problems. And I've done it at places where there is absolutely no guarantee of obstacle clearance beyond the surveyed area of the Type "A" chart. In fact, there's a very BIG chance of a big fat obstacle just beyond the surveyed limit!
Talk about being between a rock and a bloody hard place!
But
4dogs is right about the design criteria. There's always a chance that the sorts of issues that have already been canvassed here will disrupt an approach at DA/MDA, when you're committed to a landing. Because of this, your company should have a procedure to deal with it.
I know that statement is a cop out, but bear in mind that the published DA/MDA is the absolute minima. The lowest altitude that can be provided. Some operators impose higher DA/MDA through the use of approach charts that are tailored to their own requirements.
At the end of the day, safety is paramount. There are, usually, many lives that depend on official procedures, company SOPs and the pilot's own instinct for survival.