I personally like the idea of every format getting a bit of love. New cards can be created within this sets that are compatible with specified formats. To combat the "I love the way the game is and don't want it to change" every format would have two versions - unmodified and modified. Simply, you can play with new cards or not.
I know this is more complicated when generating the cards as you will have to decide what format each card is intended to work with. The other potential issue is that the set itself will have no underlying purpose other than to expand existing playing formats.
Given this is a DC set, if you create cards that support every format of the game, you are promoting every aspect of the game. More members are likely to show an interest as you are guaranteed to be working with their favourite format, whilst at the same time expsosing them to their less preferred formats.
Just my 2 cents - i am sure there are many who don't agree with me.
Well as I said, I think any good set has to support all formats in some way or another. And, if done well, it will not lose cohesion by doing so. But perhaps Movie Block is a slightly different kettle of fish given that it is in some ways a done and dusted deal? (is it like releasing a card in the latest MTG set Rise of the Eldrazi for Kamigawa block constructed?)
Anyway, apart from that aside, expanded will definitely be catered for regardless, so will standard, tournament, casual etc.