That's too bad. I'm on my 2nd Keystone and I've been happy with both. Keystone Springdale and Keystone Outback. My Springdale had one drawer that kept falling off. I finally had to do some fabrication and never had problems with that again. My Outback had one screw missing in one of the cabinets. Simple replacement ... I found one laying on the floor. We had the Springdale 8 years. Only problems were self-inflicted. But did have a few minor kinks to work out at first.  Our Outback was live-in ready. Have not had a single problem, except stuff we wanted to do.  Front cap faded within 2 years, but Keystone paid for a re-paint, all is well. 
About things like de-winterizing and such. Dewinterizing is as easy as  running water through your lines. That's all you have to do.  When you did your PDI when you took delivery, you should have had the dealer run water through the system. 
Sorry, I just don't understand your tire issue.  Considering you took the trailer to a DOT agency, are you planning on using this camper for business purposes? I have NEVER heard of anyone ever having a "recreational" vehicle inspected by DOT for any reason, let alone, issue a ticket ... but maybe if the trailer is intended for commercial purposes.  I agree with the poster above, something doesn't sound right here.
Every camper has some issues when purchased new.  You've got to learn how to prime a water pump to get it to suck right. That's not the fault of the manufacturer, that's the nature of the pump. Now that you know how to get it to work, it should be a non-issue now. There is a learning curve with every (new to you or me) camper. 
Considering YOU accepted the camper at delivery, you pretty much accepted the camper as it is. The manufacturer will stand behind the 1 year warranty. But the dealer may not be able to get it fixed as fast as YOU want. There are others in line ahead of you for repair and warranty work. 
And FYI ... "lawyering up" can be very costly. You can rack up a pretty expensive bill, real fast. However, if you are using the camper for business purposes, this throws everything into a different ball game.