Zombie Redshirt wrote:
Suppose an older version of you came back in time to when you were 15 and showed you how to drive. It would still take you practice to master the art no matter how good the instruction was.
But the link isn't like that, I don't think. A more apt analogy would be, "Suppose an older version of you came back in time to when you were 15 and and gave you his memories and knowledge about how to drive."
Is the changeling-to-changeling memory sharing perfect? Is it everlasting? Is there perhaps an element of "muscle memory" that needs to be taken into account when shape-shifting? Having the memory of being able to do something doesn't necessarily translate into the perfect ability to do so. Maybe changeling linking is more impressionistic and dream-like and less like copying files between computers.
Even in the Great Link, the other changelings were able to mislead Odo into thinking Gowron was a changeling. So I doubt that changeling linking is a perfect method for memory transfer.
Besides, in the context of the episode "Children of Time" if Old Odo "never existed", then Young Odo could not have any memories from him! We know that's not what happened, but perhaps the memory faded after the incident due to the timeline shift.