Yea it feels slow prob cause of the ecvt but if you look at the speedometer it quickly picks up speed. The 2GR engine in the gen3 is a beast and I think you can install a supercharger to make it even quicker.2005 Deville ranges from 6.2 seconds to 7.5 seconds. I currently own a 2005 Deville, and a 2023 Sienna XLE.
Having driven both extensively, the acceleration difference is "no contest". However, I agree the Sienna is much quicker than you think. In part, this is because I always drive the Sienna in "Eco" mode, where "sport" mode is much faster.