I feel your pain, brother. I went through all of this a few years back. AppEngine was still pretty new back then, so it all seemed like things that they would fix before long. But it sure didn't feel ready for production.

I'm actually quite surprised that all those same limitations are still in place after all this time. I guess if I took a minute I could come up with an issue or two I had back then that has been fixed since, but his list of show stoppers are all things that people were complaining about, and that Google gave the impression of being on top of.