I am now using the laptop cooler that I bought (a KLIM cyclone laptop cooler) and it keeps my MBP13" completely cool.
If this overheating problem is a design issue, then it can't be repaired. And there would be no point in trying to replace my 13" with another because it would have the same problem. So for me, a simple laptop cooler solves the problem.
A lot of my work involves including graphics, and I have a lot of graphics files on Keynote. So in order to preserve access to those files, and be able to modify them for other uses, I need to stay with Apple.
Yes, it's disappointing that Apple dropped it's ethics and released an (expensive) laptop that it probably knew would have these heating issues - or if it didn't know beforehand - did not make any noises about making things right for those of us who purchased it. I suppose they could claim that other laptop brands also have heating issues, but setting the bar low isn't much of an excuse.
However, I would be cutting off my nose to spite my face if I insisted on a full return of my money, then bought a PC - for then I'd lose hundreds of my hours worth of my Keynote files.