I have a gasser of the same era. I am very happy with the basement AC. Yes the basement air makes some noise, but roof air units are also noisy. On a hot night, I'd rather sleep while my basement AC runs nearby vs rear roof AC running nearby. As a Floridian, there are lots of hot nights..and certainly basement AC is nice during the day. If you live in a milder climate, your needs and impressions might be different. For example, in a mild climate, some might be able to maintain a reasonable air temp running only the roof AC further from the humans.
Admittedly, I wish Winnebago designed the roof cove differently, but once one knows about the issue (as you clearly do) it is not such a big deal to inspect and maintain that important seam. I did not know the importance of that seam when I purchased my rv, and I am very glad I learned of it before roof damage occurred.