I'm very interested in seeing this feature - when implemented do we need to update wp cli in anyway?

I'm very interested in seeing this feature

Glad to hear :)

when implemented do we need to update wp cli in anyway?

Yep. When the new version is released, you can just follow the same installation instructions you started with to override your existing version of WP-CLI.

Brill, thanks. Is there any easy way to be alerted of new updates that are in master?

Is there any easy way to be alerted of new updates that are in master?

Your best bet is to follow @wpcli on Twitter. But I think that's a reasonable feature request: #1011

@scribu Ready for a review here. If you think it's ready to go, just need to add some usage examples in places before merge.

Seems like wp menu location assign and wp menu location remove would be more consistent than wp menu assign-location and wp menu remove-location, respectively.

Also, what about renaming wp menu theme-locations to wp menu location theme? We could even go for wp menu location list.

$ wp menu create test
PHP Notice:  Trying to get property of non-object in /Users/User/git/wp-cli/php/commands/menu.php on line 57

2. Inconsistent naming: wp menu item remove vs. wp menu delete. (Also see wp widget delete)

3. wp menu delete and wp menu item remove should support deleting multiple elements.

4. <db-id> in wp menu item * <db-id> could just be <id>, no?

1-3 have been addressed.

For 4, menus have multiple "ids", so I went with <db-id> to be specific.