Firstly, there are still some serious uses of MyISAM - it's very fast for dumb things, so when you
don't need transactions, locking, etc. then it provides a good option. Also, it wasn't that long
ago that some of the fancier options (e.g. replication) were only supported by MyISAM. I do
agree that InnoDB is better in most instances.
Secondly, if they're going to change the default storage engine then I hope they go with Falcon
rather than InnoDB. In my opinion it is substantially better.
Thirdly, Oracle has a number of database products (Times 10 and Berkeley) and is not remotely
averse to killing off products when it sees a long term advantage in doing so. Just look at how
terribly they deal with products like Discoverer, Forms or Designer.
I don't know what will happen with ZFS - When I tested it in a deliberate hardware failure I
managed to corrupt all of the data after removing just one drive, which put me off exploring it
further (that was almost five years ago). I'm really holding out for a proper distributed filesystem
and Sun has much more potential to release one than any other company. It's possible that could
fit well with RAC or else Oracle may see that as competition as it brings replication to a lower
price tag - hard to know but that's what I'm going to be watching for :)