* a global server lock

It's gone

* The query engine of MongoDB still can only use of one index per query. How insane is this?

MySQL uses one index per query and it's fine with that. What else do you want? It's a tree index, there's no any magic there.

* Having no option to perform an operation comparable to UPDATE table SET foo=bar WHERE..

In fact, you have that option. That's what modifier operations are for.

* there are already too many moving parts in a setup for scalable applications.

Oh my god! Creating scalable applications is hard! I thought MongoDB would do that for me, but it did not.

I think that no-nosql hype is even worse than nosql hype. That's when you suddenly realize: no, it's NOT WEBSCALE.