I don't disagree that it is not as fast as a true sport tuned DSG. but saying it is not any better than a 2008 transmission is a bit much. I don't know when is the last time you manually shifted an automatic transmission from that era, but those downshifts and upshift where the slowest thing ever. Compared to the transmission in my 2010 mazda and 2011 ford, the CX-9 manually shifts very quickly and a lot more satisfyingly. Paddle shifters are available on the 2021 CX-9 and have been for a while in the other mazda models, and the sport mode is just a shift point programming variation (which could be ok but this isn't an engine that's meant to rev high).It is better than a CVT for sure but is not any better than the auto transmission we have in our old 2008 Sienna Minivan with 200k miles on it. The "sport" mode in the Mazda is a joke, no paddle shifters, manual up/downshifts are slow-ish ... just like with every traditional AT.
DSG also have their disadvantages, especially when not done right ( I am looking at you Hyundais, Kias and lesser VW models). Adding a few ratios would definitely help with the fuel economy, but manually shifting an 8 speed transmission is boring as hell and very annoying (trying to figure out how many downshifts you need to get what you want isn't easy).