Depends what you consider "too much". If your battery can only be charged to 9 out of 12 bars after five years (which is considered acceptable under the warranty), that means you've lost 25% of your battery capacity, or 25% of your car's range.
Since after five years it will only get worse (and the warranty will have expired), it also suggests that nobody will want to buy your five year old Leaf unless you discount the price by the cost of a new battery (several thousand dollars).
Gasoline powered cars don't have either of these problems, which suggests that electric cars will remain a small market unless the price of gas goes up sharply.
or battery technology improves substantially which seems likely either in capacity or price, but probably both.
I think this will become less and less of an issue as these cars become older and more common. On the other hand, if this does kill the resale value, I will be all over a cheap electric car and replace the battery myself.
I would hazard that Nissan has performed a number more tests on the leaf batteries in the last couple years and developed a better model for battery decay based on their enforced management of the above listed characteristics.