I had the (I) and sorry I settled for the 4-cyl. I was coming out of a '06 Hyundai Azera Limited (0-60 in 6 flat) so the '09 felt severely under-powered and not especially sporty either. I also lost a ton of features including power rear sunshade, power seats/pedals/wheel, awesome stereo, etc. At the time, I thought it was best to lease a less expensive, more fuel efficient car. So not many fond memories of that car but the '16 was truly a great car.
A few other things I wish the '18 offered. Very minor stuff but worth mentioning:
Door handle sensors are pretty common now. Nitpicking here but if you drive another family vehicle that has it, you will keep forgetting to hit the button on the Mazda. Those door buttons rotted out on my '09; no issues with the '16.
TPMS that displays the pressure in each tire.
Bigger sun visor. If you are not tall, the sun visor is basically useless because to comfortably rest your arms on the armrest, you are forced into a low seating position.