Logs are excellent insulators, and emit a wonderful fragrance that will never go away.

Once I closed on the property I started to tear down the walls and notice that had no insulation, at that point I decided I going to tear  everything up. when I took the sheetrock from the ceiling, I was in shock to see that some electric work was done with duct tape. 

Is there a better way to improve insulation.

Insulate, add electrical, mini-split ac, and possibly plumbing, as desired, drywall, tape and paint, put built-in cab's on one side if you want, hang the tv, speakers, etc, install bi-fold/multi-fold doors on the side leading to a patio, and replace the garage door with an insulated one keeping the track and removing the motor, or install a carriage type garage door into the existing garage opening.

Follow the same guidelines and consider letting an outside company manage your property to give you a layer of insulation. 

To make a long, expensive story short, we discovered that builder failed to insulate an entire 3rd attic space and didn't seal wall cavities up in the main attic or insulate chases properly (Inspector failed too). 

So, they will need to remove insulation to access all joists/floor boards.We agreed Dehumidifier to be installed to prevent the issue from reoccurring.I already have vapor barrier installed.Crawl Space Ninja stated that the fiberglass blanket insulation between the joists in my crawlspace can remain removed post remediation.

When I rehabbed the basement I tore out the existing drywall ceiling and added sound-proofing insulation followed by a 5/8" fire-rated drywall thinking that would be enough, but apparently the tenants can hear us walking, the dogs claws (we have hardwoods) as well as the TV.

You still have to fur out the inside to put insulation and drywall on.

Superficial Improvements: The focus on aesthetics might mean that only visible areas are improved, while critical but unseen aspects like plumbing, electrical systems, and insulation are neglected.5.