Perhaps it is taking away a "feature" in some senses, but in my view it is taking the logical step not allowing concurrent access to preempt during execution. I often want the current value that has changed after the original context is changed by an asynchronous task (IP addresses of internal servers changing while a script was running came up today).

There is no way preempting access / memory contention is a feature, but Clojure avoids this with somewhat immutable state which can make keeping up to date values painful, although I may not be experienced enough to state much about Clojure.

For web services such as ours where we have values changing underneath us it is elegant that we keep a value the same through a single flow of control (until the stack unwinds). Even if it is incorrect for one part of the task as a whole, it is predictable where the values can change and dealing with errors from pointing to the wrong object / value is trivial compared to most race conditions (yes, node does those before anyone jumps in).

The environment here is key though. Node was built as a single threaded event loop. All the bindings for node / libraries for node expect this. Libgmp's love of aborting threads after a process gives it a wrong value is a good example of where the single threaded environment fights the threaded model, and the same problems of expecting threads is apparent in many programming environments (.Net Http stack I'm looking at you).

So in many ways: Node does not give you something that cannot be done in other environments; but, in other environments there is a lot of existing code that encourages thread usage. Doing something in twisted or the like proved difficult once I needed libraries that had been written expecting threads. The same is true in Node, but I can be confident that good libraries / bindings for Node provide things that expect to work in a single threaded event loop. And I like the command queue / event loop / actor based / reactive / whatever you want to call it. I like it more than anything due to the lack of concurrent edits, but allowing a lot of mutability at the same time.