Having done the work of observing langugage users apparently want an ordered map, were there any steps taken to add such a facility, or did efforts stop at letting developers know they were they were wrong by taking away a de facto feature?
Ordered maps require other tradeoffs. For example, c++ has both: std::map and std::unordered_map. std::map is a treemap, and so has logn access/insertion times. It also does a ton of small allocations, and scatters your data across memory, leading to poor cache performance at scale.
But it has ordered output, and doesn't invalidate iterators on insertion (hashmaps might, because they sometimes need to rehash).
Generally, the suggestion that I've heard is to avoid using std::map unless you really really what it specifically provides, because it's expensive and it's hard to know if you can safely relax those constraints.
C++ ordered maps are in sorted order whereas php-style hashes are in insertion order (recent versions of Ruby and Python have adopted the php semantics; in JS maps are php style but JS objects are unordered)
The biggest advantage of trees is deterministic complexity. There's a bunch of DoS attacks that exploit hashtables, because they can be O(n) in the worst case - and if you control the input, you can deliberately make it worst case. Most "secure C++" guidelines recommend defaulting to std::set and std::map for this reason alone.
If you really need an ordered map, implement one in Go isn't too difficult (but the usual no-generic caveat applies). You can just define a struct that wraps a map and a slice (or some other data structure) to record the order of the keys.
If you want it to be performant, a linked list is better than a slice. Then in your map you store structs that have both the stores value and a pointer to the corresponding node in the linked list. That way random deletions are constant time since they don’t require copying the slice.
