I'm more concerned about possible loss of the HDD than I am about the optical drive. Most people don't use their optical drive on a regular basis anymore, so it makes sense to get rid of it and expect that they'll use an external drive when needed. If the MBPs move to all SSD, however, that will be a huge issue for a lot of people. Many (myself included) can't make due with 128GB or 256GB as our main storage, and expecting people to carry around an external HDD at this point isn't practical. Until the price of SSDs comes down enough to allow more capacity, there still needs to be an HDD.