Many times I will change one load, for example a seismic load which is palced at the Ridge. Then I have to reanalyze and redesign the entire model, every load case. There should be a way to analyze only the affected load cases and redesign only the affected load cases as long as the the model is already analyzed and designed. 
For example,
An unanalyzed model: Nothing changes.

An analyzed model, undesigned: pop up which asks if I would like to reanalyze for the affected cases. I could choose no and would lose all analysis, yes, would reanalyze only affected load cases.

An analyzed and designed model: Again, pop up, but asks if you would like to reanalyze and redesign for affected load cases.