Figuring the highest value increasing repairs can only be done case by case. It all depends on the sub-market and the existing improvements. Sometimes the highest value increasing repair is to not make any repairs. Sometimes it only pays to repair one component if other components are also repaired. What you need is intimate market knowledge specific to the particular property, not some fantasy magical universal mathematical formula to apply to all property components in all properties.
The value of real estate is a function of the whole. The value of real estate is not a sum of components.
What you need to do is look at other homes in your market and see what others have done and what they end up getting for their property, both low and high ends of the spectrum. In this way, you can establish what you might expect to get if you do nothing, and what you might expect to get if you do everything. Establishing what you can expect to get somewhere in the middle is a crap shoot, and it actually comes down to the individual buyer, not some formula. It's about establishing what is typical and generating a strategy based on that, with the understanding that the world of real estate is not typical and always variable.
This is why realtors generally recommend you repair what is broken, because all buyers dislike things that are broken. This is why they will recommend neutral paint and finishes, as these offend the least amount of people. This why they do not recommend you repair a property with your own tastes, as your taste may not be (and usually isn't) universal.
Trying to understand all of this component by component is the wrong approach. You have to assess each property as a function of the whole.
For instance, if you have disgusting carpeting, it might pay to replace it. However, if the rest of the house is a ****-hole too, why bother? All you did is put lipstick on a pig. But if the rest of the house is nice and the only thing that stands out is that disgusting carpeting, it is likely a good investment to replace it.
Last and not least, sometimes the "value added" does not come back in dollars, but rather comes back in marketing time. This idea lends itself to the fact that all real estate can probably sell for more if it listed it long enough. This is why all appraisals are contingent on a marketing time frame for instance "$100k with an exposure time of 3 months".