"This thread pool is not well abstracted typically, and the mutable object model leads you to writing classically tricky multithreaded code with data races and

"This thread pool is not well abstracted typically, and the mutable object model leads you to writing classically tricky multithreaded code with data races and the like" : If each request gets its own thread I don't really see the problem (they will not override each other's shared objects). Yes you sometimes run into stale reads/writes which you can solve with db locks etc.