I think the throttle response has more to do with the fact that it's just a really low-power engine. If you're below 1500-2000 rpm, "nobody's home". Once you get above 2000, throttle response improves. And if you're up around 4000, it's just fine.

I had an engine torque strut on my car for a while, I found that helped with throttle response A LOT, too. We have soft engine mounts to try to counter some of the natural vibration of the 3-cylinder.