I haven't towed with a JX yet. I have towed with an older MDX (2001). So take my comments with something of a grain of salt. I've also towed with other vehicles. Here's my take:
If your boat comes in under 3500lbs loaded, you should be fine. The biggest variable I've found with towing is wind resistance. If the boat on the trailer is notably taller than the JX, and/or if you are going to tow with a big top/windshield up on the boat, you'll probably notice a lot more drag than if your boat is lower profile, doesn't have a bimini top creating extra drag, etc. I used to tow my motorcycles behind the MDX a lot. On a flat trailer, it was easy - almost like I wasn't towing anything. When I borrowed a neighbors small box trailer it was different. His trailer wasn't that heavy, but it stuck up above the roofline of the mdx by about 3 feet. That added wind resistance dropped my fuel economy by almost half, and dramatically changed the handling characteristics. I had much more drag in acceleration and really felt it pushing me when braking (no brakes on the trailer).
The other issue is whether you'll be towing up/down big hills. If yes, you're also more likely to stress the car at the margins.
So if the boat on the trailer will be fairly aerodynamic and stay below or close to the roofline of the JX, I'd think you'll be fine. If not, maybe you need to wait for the Pathfinder or if they update the drivetrain in the JX sometime next year to be the same system as the pathfinder.