These nuisances didn’t rise to the level of evicting the tenants, so basically I just had to suffer.

Sure it suffered due to COVID, but you want to buy when there is distress.

What is your process for re-valuing properties as the appreciate in value or suffer value declines?  

Some people are scammers, some are disorganized, lazy or suffer from mental disorders where they get frozen and do nothing.

The quality of tenants may suffer as a result.Is it worth it?

If so, how much will the income from your current investment suffer?

Even if the exception was deleted however, the policy probably has an exclusion for matters suffered assumed or agreed to by the Insured, which would remove coverage for the matter. 

One of my rental properties suffered water damage and I'm wondering if I should file an insurance claim or just eat it...?

TLDR: If we stop using it as an apartment (not planned) or if it suffers more than 50% of it's value in damages (fire or other act of god), then it would no longer be grandfathered in and must convert to SFH.

As a result, it suffers from some of the same issues the Midwest does as a whole, and for the past few decades has not seen the same kind of growth as other parts of the country i.e west coast and sunbelt.