Because of this I moved away from GAE over a year ago. And not me alone, when GAE was still hot, 2-3 years ago, you could read tons of blog articles with unsatisfied customers.

So it doesn't surprise me to read about weird performance degradations. Since years GAE suffers from such problems.

Maybe they don't care about small customers and love to hear about them move to Heroku or to good old Virtual Servers. It would be polite to tell upfront though.