[Sal]

According to the source the shift shows how much Kim Jong-il is afraid of the power vacuum that his death might cause,

OK, I guess pretty much everybody figures Kim is worried about his own impending death, not the path of succession.

Is there any known or suspected reason he might actually fear a NATURAL impending death and thus actually care about succession?

[ASA Vet]

Is there any known or suspected reason he might actually fear a NATURAL impending death

I suspect he knows he's not a strong swimmer.

[TigerLikesRooster]

He is in bad health. Suffering from heart problem, and diabetes, among other things. It is affecting his gait(walking) and his eyesight. Experts disagree how far gone his illness is. After all, these are chronic ailment. Still, lately, U.S., China and even S. Korea started to worry about this possibility, even though there is no published article which reported anything other than known information outlined above.

I can think of two backdrops: (1) N. Korean system and society are showing symptoms of an organization at its last leg of life. Things are falling apart. N. Korean regime has been frantically trying to reassert control with various measures. It all boils down to ban people from being engaged in private business, escaping N. Korea, communicating via cellphones, and bringing in stuffs from outside. Kim Jong-il wants to put Genie back to a bottle. It is not going well. His regime has been slowly falling apart, but its pace picked up lately. (2) His ailment is worse than media reported, and succession process is not progressing smoothly. Powerful factions are evenly matched up, hampering easy resolution. The stakes are really high, and there is also almost certain chance of foreign intervention if things go wrong during this power struggle. So Kim Jong-il needs to forestall any potential dangers such as his military meddling in. However, it can invite another danger such as alienating military for good.

He is in no win situation, so to speak.

Everybody including U.S., S. Korea, and China put up business-as-usual facade now, but somehow I find it deceiving, in light of sudden media exposure given to potential contingency plan for N. Korea's breakup.