Debt service coverage ratios are usually used on income producing properties to measure the property and its value 

If forced to “legalize” it with permitting, either ask if they have “prescriptive measures” for deck framing you can review and see if it matches, or hire a Str Eng to investigate and draft a plan that matches the deck + any retrofitting they feel is necessary.

I've never purchased a property wholesale, and I do exceedingly well on the SFRs I own by any measure, so I think there are many ways to buy deals, esp. in an appreciating market like Phoenix.

They are successful because they take calculated, measured risks.You made sweeping generalizations about BP members.

It looks like Fannie Mae is taking measures to qualify millenials with boatloads of toxic debt.  

You can institute the punitive measures which should be in your lease for that breach such as a fine, etc.

BUT, for good measure, I also contacted an experienced builder (not located in the Houston area) and he said, for various reasons, to either deduct the max costs you might need for the repairs from your offer, or walk away.

Unless you are doing a commercial loan or dealing with a portfolio lender they are usually structured to be sold into the secondary market and so the requirements are much more stringent.

And though the system is imperfect, it does add a measure of protection for all the parties involved. 

It's a measure for a given market at a given time to compare assets on an equal footing.