seems not yet understood
bitcoin is merely a term for an implementation of transaction way
the way is so simple, first that force every player to obey the rules
it's deploying simple algorithm singly linked list with the data in Merkle Tree data/hash structure
The refactoring is called Ethereum.
So, looking at it from a project management point of view: it's working. Insert as many asterisks, fear quotes and footnotes on that first sentence as you feel is appropriate, but, generally, it is, for better or worse. I think, like other working software out there, it's not degrading, so the only impetus for refactor is changing external conditions (expectations, medium, usage, etc.). This has been happening gradually. On the other hand, my understanding is that direct stakeholders (miners) are extremely resistant to change, unless it solves an existential problem in the medium, as they don't want to mess with their setup they have. I would not call these ideal conditions to see a refactor of code take place, as that holds risk and offers no benefit to stakeholders in their view.
The rest of the world seems to agree, as people who wanted big change made other coins that are faster, more private, etc., and other people who wanted Bitcoin to be less shitty devised things like the lightning network, which is a protocol on top of it.