Normal mode = castration mode. 'Sport mode' should be called 'track mode'. There should be something else in between which has the better shift points & throttle response of 'sport mode' but which quickly stands down upon removing near WOT inputs instead of hanging around for 30 seconds at >4kRPM.
A friend of mine got his '17 reprogrammed at my advice and is now raving about sport mode. He used to drive 100% in normal mode. He said he had to have a couple things reprogrammed (I will check what they were later), and the second iteration was night and day for his truck.
I don't think it's 100% hardware related, but the 8 speed ZFs I've driven somehow manage to shift firm without feeling like something is going to be broken and/or are at least consistent in their shift harshness. I'm ok with hard shifts, but the fact that this transmission's harshness appears to be gear dependent (shifting to 5th?), temperature dependent, and otherwise somewhat randomized is annoying.
I'm going to try out what he did at some point in the next couple months and will report back with the results.
FWIW, I drive in sport mode ~24x7 when on the street, but I usually use manual mode because I don't like it hanging at very high RPM long after I'm done pointing and shooting. However, as stated before, the lag between command and actual shift is also very annoying. Except for some rock crawling scenarios, as with most vehicles, I'd really like to see a DCT in this truck.