Who cares? Is any of that particularly valuable? Setting up your language prefs again surely only takes a minute or two.
Not having to skim through already-watched or downvoted shows is a gain of time, which is probably valuable if one takes the time to (un)subscribe regularly.
You don't with most of them. I do the same as OP. With most of them (Hulu, Prime, and Netflix) you are just "deactivating" it so they don't charge you. All your watchlists, settings, etc. are still saved, so once you resume the service you still have all that setup. It's really not a hassle at all.
You don't with Netflix - you can just re-subscribe whenever you would like.