You frame rates were already very low before the udpate and are very low for KLAX too, which means the problem is not the scenery, but you configuration, or you settings, or your AI traffic models.
The problem might just be too high settings for your system, and too much memory taken, this could explain the fact you don't immediately see an increase when setting traffic to 0. If requires a restart, then you can be *sure* it's a memory problem. Again, nothing related to the scenery, if it's the AI setting that requires a restart to get a frame rate increase when setting it at 0, it's sure the problem are the AI models.
The only thing different from previous version, is that we increased the visibility range of the smaller objects, but this can't cause a big fps loss UNLESS your system was ALREADY in the "red zone", with resources already on the verge of exhaustion so, just loading a bit of more object, resulted in a performance collapse. Again, this is nothing related to the scenery, if you were in that situation, it was already critical.