It'll be interesting what they do with the last episode of The Crown. I know they've said that it will end with the Queen Mother's death, which makes an amount of sense, but I was thinking just now that I wonder if they'll fade that into a "what happened next" text ending or something.
And, semi-related, I've been saying for a while that after The Crown is done they should go a bit further back in time. But Victoria has been done a lot. The Regency has been done a lot. The Tudors has been done excessively. So keep going further. A series which opens with the death of Edward the Confessor in January 1066. The first series ends with William The Bastard's coronation the following Christmas. Then you carry on and have ~1000 years of history before it becomes awkward again, and hopefully by the time you reach the Wars Of The Roses it's been a while since the last Tudor thing.