It's not necessarily a problem, but it's a smell. Modern object-oriented PHP development is done with autoloaders[1]: having to require_once every class file is unnecessary and brittle. It is odd that GAE doesn't provide its own autoloader for its provided classes, and I'd expect that to be addressed in the future.

[1]: http://php.net/manual/en/language.oop5.autoload.php

without autoload its seems useless and as monster. Its seems as broken by design.