I would be surprised if it were otherwise. People forever underestimate the difficulty of building a truly new design. The Leaf may be battery powered but the drive-train is a comparatively small part of an electric vehicle. Most of the vehicle draws parts/technologies/manufacturing processes/suppliers/people from other Nissan models & lines. So Nissan has a dramatically smaller hill to climb.
Further, in producing a high power/high performance vehicle Tesla has made their job much tougher yet. So many things get more difficult when you're looking to put 500+ HP to 4 wheels instead of 120 to 2. And the challenges are exponential, not linear.
As I've said numerous times... the shocker is not that Tesla has had problems. It's that there have been so comparatively few. And Tesla has dealt with the issues admirably well so far.
I agree. Tesla is out in somewhat uncharted waters with the drive units. Other electric cars and even hybrids have electric motors, but Tesla is the only company mass producing high performance cars with electric motors. If you read some of the drive unit threads here it becomes obvious the high power going through the drive units has had some unintended consequences nobody really anticipated, or even saw before. It's basically a scaling problem. Something that wasn't a problem for a motor running at 100W becomes a problem when the same application it using 300+ watts.
Tesla was able to make the safest car ever built (I think only two people have died in Teslas thus far and both were weird accidents), produce a car with way more horsepower and performance than any sedan ever built, build a decent work around for the range problems on long trips, include more technologies never put in cars before this on top of the electric motor, make it look attractive, and have as few problems as they have had is just fricking amazing!