There's an obvious plot-hole in the episode "Children of Time" that I've always been curious about. Odo is unable to hold his shape because of the effects of the barrier sounding the planet, but his older self has learned how to counteract the barrier's effects. He's also "gotten better at shape-shifting," as evidence by his improved ability to imitate humanoid facial features. Near the episode's conclusion, the older Odo links with his counterpart, so that the younger Odo would be aware of events that transpired while he was regenerating. This being the case, why didn't Odo's shape-shifting abilities improve as a result of the experience? I do, of course, understand the logistical reason for not making the change. Odo's lack of facial features was part of his character, and a sudden change may have confused viewers who missed "Children of Time's" original airing. I'm also aware of the other plot-hole in which no explanation is given for how the other Odo didn't develop the disease that nearly wiped out the Great Link (beyond the fact that the idea hadn't been conceived yet). However, would it not have made sense from a character-development standpoint for Odo to have made significant improvements in his shape-shifting ability?