There are other option available in the future. Including, but not limited to, simply including a recent copy of the blockchain in each new client release to be downloaded directly rather than over the p2p network and verified by each client upon first start. It's the verification process that takes most of the time, not the actual downloading.
If they do decide to include the database they better hope it compresses well. My data directory for bitcoin is at 1.8GB and growing. That's only with 131340 blocks AND an empty wallet that has not yet made any transactions. Who knows how big it will be in five years
