Your writing is just fine far as I'm concerned...
I just 'schooled' a potential used TC buyer about what to look for with any unit and that includes a TT or a 5er or even a motorhome and TC.
When looking at a used unit, skip the fru-fru **** and open up the cabinet doos and have a hard look at the seams where the interior walls meet the floor.
With a 5er and a TC, lift the mattress and look at the seams and with any unit with cabinets in the cab over, look inside. Look hard at the floor near the entrance door and if possible get on the roof and see it it's soft or warped.
Water intrusion can show in corners, behind cabinets and under the mattress and if it's showing any sign of intrusion, it will be 10 times worse under the wallboard.
I've seen a few campers that looked pristine on the outside that were being held together with the outer skin and had no structural strength at all. Most of it comes about when owners don't bother to check seams and re seal as necessary. I do it twice a year even though mine lives inside when I'm not using it.
With a TC, one sure way to tell if the structure has rot issues is take a look at the tie down plates, sighting along the lower edge, front to rear. If the tie down's are not square or appear to be sagging, chances are real good that underneath the skin, the wood is rotted.
I agree it's poor maunfacturing techniques and a hurry up and get it out the door philosophy on the builders part.
My next TC will be aluminum framed bit even that don't preclude water damage from neglect in sealing. It takes the rotted structural member out of the equation but there is still the possibility of water damage to other items inside.
The one major leak point is the cab over bunk. I always look real hard there when looking at any camper TC or 5er.
I've always maintained that while it may look like a silk purse, underneath it can be a sows ear.