1. admin can assign more than one condition to a field

The interface for edit field isn't ideal for this, so not going to happen. Please understand in the more then 3 years I have been a part of the team and sense CBs birth no one has created a conditional plugin so CB can have conditional fields. This was significantly more difficult then one would perceive and do not wish to add further complexity to it in risk of breaking it.

2. hiding a field would hide any fields that depend on it

When using "Condition Self" next release will force the field to hide it self if the field it depends on is also hidden.

3. admin can choose to show non-field elements (like captcha) within or outside a step on the registration form

There's no way for CB Conditional to know what is what. It's purely jQuery driven and simply grabs what isn't a tab and throws it in its own tab. No plans to change this behavior.

4. admin can choose to save the steps progressively such that if a user aborts the process midway he can be registered (provided the required fields are completed) and reminded to continue the process at login

Not possible, Step by Step is just dynamically altering the display of registration; nothing more. The same registration workflows applies with or without step by step.

5. admin can label the steps (e.g. change "Step 1' to something else)

The steps are language strings and you can define them as something else in your language plugin. This is explained from backend when enabling step by step.

These are my feature requests, arranged in order of priority. It would be nice if you could submit them to the development team and revert on which features have been adopted and some indication of the road map.

There is no development team for CB Conditional. I am its sole developer and creator; please see comments to requests above.

I had no plans to implement show/hide of select fields values. The problem is even with this feature you still couldn't do what you're wanting because multiple conditions aren't supported.

It's possible I'll create a conditional country > state > city ajax drop-down integration as an incubator project, but certainly wont be anytime soon.