I guess the general advice is do not take delivery before everything is working correctly, and you have the correct price nailed down.
Most are reporting that they are getting around 20% off the manufactures retail price, and are not paying a extra fee to have the RV prep for delivery. Some manufactures price their units pretty high, and leave 30% in there for dealership profit, and those brands you can get upwards of 25% off the MSRP.
Once you take delivery, the unit is yours. The dealership has no reason to hurry anymore, he is not paying $400 a month in bank loan interest! Sad but about the only thing you can do is make up a huge sign and sit on the street near the dealership describing how you are getting screwed out of the use of your RV by this dealership who is not repairing it in a timely manner.
They should have enough mechanics to repair them. Problem is they probably want to hire mechanics for $15 a hour, and are not getting qualified mechanics who will do the work quickly and correctly. So the unskilled mechanics are having to spend time reading a installation manual, or calling technical support help line, instead of taking care of the problems. And without the proper number of mechanics, they can not churn out the repair work quickly, thus they have a backlog of units needing to be repaired.
That was what was happening when I bought my motorhome. Seems they can help a lot when you are looking to buy, but are not so helpful after they have your money.
Sad,
Fred.