I think the concept works (ready action until condition expires). You just have to be careful how you word it.
You cannot delay your entire turn until you are no longer immobilized (or whatever), because the harmful effect will delay right along with you.
But you can prepare a specific action and have it be triggered - not by the end of the condition, but by any opponent taking an action after the condition has ended (the wording of the trigger may have to be more specific - perhaps an attack or a move - depending on your DM).
This has the same net effect (your delayed action takes place after your turn has ended and the immobilization has terminated) and your order in the initiative is unchanged (your new place is the same as your old place).
And, of course, there is always the chance that you will never gain an action that round. For example if you are dealing with immobilized (save ends), you are choosing to give up a certain action while immobilized in exchange for a conditional action that may never occur (if the immobilized fails to end, you never get to act).
Carl
You cannot delay your entire turn until you are no longer immobilized (or whatever), because the harmful effect will delay right along with you.
But you can prepare a specific action and have it be triggered - not by the end of the condition, but by any opponent taking an action after the condition has ended (the wording of the trigger may have to be more specific - perhaps an attack or a move - depending on your DM).
This has the same net effect (your delayed action takes place after your turn has ended and the immobilization has terminated) and your order in the initiative is unchanged (your new place is the same as your old place).
And, of course, there is always the chance that you will never gain an action that round. For example if you are dealing with immobilized (save ends), you are choosing to give up a certain action while immobilized in exchange for a conditional action that may never occur (if the immobilized fails to end, you never get to act).
Carl