Would also be interested to hear more about the "deployment nightmares with Zookeeper". For us, it has to be one of the most stable pieces of 3rd party server software we run.
Lots of things can and do go wrong with Zookeeper. I suspect it depends on the use case, but building a Zookeeper dependency into any system is potentially asking a lot of users/operators.
Ideally, these kinds systems should be built such that the distributed coordination piece is pluggable and the implementation can be chosen based on deployment concerns.