The block size issue has the possibility of crippling satoshidice.
Unless they start doing things more efficiently the network will act to defend itself one way or the other against the SD "attack" whether through increased fees or blocking SD transactions altogether. SD may have to invest in its own mining equipment if it wants to continue its wasteful ways.
Are you serious?
Bitcoin won't block S.DICE transactions. They are already paying twice the needed fee.
There's no such entity as a "Bitcoin" that can choose whether or not to block or not S.DICE transactions.
Any blocking would be done by individual pools. It would only take one large pool to actively be hostile to S.DICE to make them unable to allow zero-confirmation bets at all. If a pool discards S.DICE transactions but intentionally allows competing transactions from same source to process then the pool only needs a few % of network power for anyone to profitably attack S.DICE by trying to double-spend any losing bets - the few % of times the pool includes the double-spend (and cancels the losing bet) then outweigh the house edge on the rest of bets. You underestimate the extent to which some are opposed to S.DICE (not me - obviously).