I wouldn't call anything "locked" during testing and active development. Our development processes are as iterative as they've ever been, and we're always looking for places where we need to make further changes to meet design goals.
Having said that, we're close to finished with the changes to the rotations and the look and feel for most specs. We’ve still got a few changes coming soon in the Beta to Unholy Death Knights, Frost Death Knights, and Protection Warriors.
We used the Alpha timeframe to make some surgical changes to several other specs, and we're somewhat finished with that stage of development for this expansion.
In the days and weeks to come in the Beta, we're going to keep a focus on how every spec plays with regard to the new itemization systems in Battle for Azeroth. While it's certainly possible that feedback on how Azerite affects a certain spec could lead us to do further development on that spec's rotation, we don't expect to need any big changes to talents that would justify the words "severe" or "overhaul".
Beyond itemization concerns, there may be spots where we’ll do focused problem-solving around rotational issues (examples: “it turns out that simulations say never to use X, but X seems like it should be part of my core rotation” or “my spec is too feast-or-famine, and if I have bad luck with Y procs, I feel useless.”).
As always, thank you very much for testing the Beta and making your experiences testing inform your feedback. Focused feedback is super-helpful.