Let's deprecate and (in the future) remove all old ways of getting different action tokens which are now superseded by the action=tokens API
We could probably deprecate it in 1.23 (adding a warning to API calls using them).
We should probably remove them some time after the 1.19 LTS release stops being supported (it is the last version without the new API). 1.24 or 1.25, I guess.
At some point we should also remove the examples in the documentation using the old style (e.g. [[mw:API:Edit#Token]] and same for every other token) and replace them with new-style ones.