I still have all the original tenants and they really seem to appreciate me putting time and money into making these properties have some curb appeal. 

If the price is right, I find (for rentals) if they are doing drive by's and not coming inside or doing showings, something with curb appeal could be awry or a neighboring trashed property could be repelling lookers.You said you bought raw land and developed it, so it may or may not have the amenities of a standard subdivision (sidewalks, streetlights, even pavement, parks etc)..

I just saw the below opinion piece last week on Curbed and the author certainly isn't a fan of the current state of Title Insurance.   

So, it needs to be in good shape, renovated or very nice, curb appeal, competitive with other rentals.4.

It's so awful that I feel moist and filthy having just carried it to the curb, also I now have the unmistakable aura of cat pee and cigarette.

I would be tempted to kick your present plumber to the curb for starters.

If you have a contractor put in different size windows the home may lose its curb appeal and look downscale.

However, there wouldn't have been any cost for them to move their stuff to the curb and clean the apartment. 

If you can come to the city to visit that helps but often, as a majority of properties are "curb offers only", buyers will come out for inspections after the offer is made and then go home and complete the rest of deal form there.

However, shortly after moving in, a few weeks ago, the city carried out water maintenance that led to water leakage and accumulation on the curb side of the parking area.