it is NOT worth it. It wasn't even worth it at $2500 before they raised the price and especially not worth it now since the drive train is now covered with the battery for 8 yrs unlimited miles. You'd basically be paying for an overpriced insurance plan that still has a deductible anyway. I'm at 67k miles and 0 issues...these cars are built very very well.
I'm springboarding off your post because you bring up some good points, that the drive train is now covered along the same lines as the battery plus factoring the $200 deductible per repair under the extended warranty.
I want to point out that the "drive train" coverage, as far as I know, applies to the drive unit only. If I'm mistaken, please correct me, but it doesn't apply to any other parts of the car's drive train or power train such as driveshafts, joints, etc. It is specific to the motor/inverter unit only, not anything that is connected to the unit. What if your motor mounts crack, as has happened to a number of folks, would that be covered? I don't know.
Similarly, I believe the battery warranty covers the battery only. It does not cover components needed to charge or discharge the battery that are not contained within the battery pack itself. If your on-board chargers or Supercharger hardware fails, neither would be covered under the battery warranty. A single failed charger can set you back over $1,500 and failed Supercharger hardware, which happened to Goldie Bhullar (the livery driver who was supposedly asked to pay for a new drive unit), costs around $4,000. This is all based on hearsay and from what I remember Goldie posting over at the TM forums. The DC-DC inverter in the front of the car would likely also not be covered under the battery warranty.
I mention the above because some people make the honest and understandable assumption that anything charging-related is also battery-related. It's not.
Forum - please correct me if I'm wrong on any of the above.
I've read that the 17" touch screen is at least a $3,000 expense. I can't imagine what it would cost to replace the pano roof in case of a failure. Door handles are $1,000 each. Then we have the LED screen in the instrument cluster which may have its own Tegra processor. Autopilot cars have a suite of sensors and a windshield camera, I imagine those items would be costly to fix.
I think that if the ESA buys you peace of mind, go for it. I bought mine when it was $2,500 and I'm glad that I did. I think it also helps with private party sales, especially if you have to disclose your thick-as-a-phonebook service history.