Hybrid modifications for mpg

[Malibu16_hybrid]

I had a 2012 Prius C for 4 years and now a 2016 Malibu Hybrid for 3. The Prius was a reliable, minimum car with adequate mileage but too dangerous on the highway as well as far too underpowered. The Malibu is a real car - comfortable, powerful, reliable and a beauty.
The difference in mileage may be about 5 mpg less with my Malibu, but with several advantages. The Prius could not retain ev mode past 40 mph, while the Malibu will hold up to 50 mph.
I am not a hypermiler, so my mpg average is only about 38 currently, affected greatly by short 2 mile trips in stop and go traffic about 75% of the time.
Here is my question: All of these hybrids have a short accelerator stroke before starting the ICE unit, especially the Malibu. If I had less throttle response in town, I could probably improve my avg. mpg. There are gadgets out there that can vary the throttle response, designed for supposed acceleration improvements, that can also detune the response. Has anyone ever heard of using one for this application? Any suggestions?