I used to agree on the gearing, but not anymore. I fully agree on the emissions.. which also aligns with the MUCH better frame/suspension of the '14+ 2500.
Having had the 3.42's now for 15K miles I am very happy with them even at low speed semi-heavy towing (up to 24K). Direct and 3.42's is a much better highway towing gear than direct and 3.73's, so for me 3.73's are now the least desirable ratio offered.
Really the advantage to the 4.10's is in 1st gear, especially on a 68RFE truck. Above that the gear spacing is adequate for 3.42's.
So @NIsaacs I wouldn't hesitate to get 14+ and if you need the low speed improvement then get 4.10's installed, but I bet you'd be quite happy with 3.42's.
For me it's not just first gear it's all of them, yes you can hold the gear to run the rpm up but on the other end 6th is all but useless once you get up over about 10-12k and get into the bigger hills. I find myself locking out 6 quite a bit to eliminate the shift hunting. Lower gearing would help this as well as increase the retarding power of the exhaust brake through all of the gears.
As much as I'd like to change them out the system admittedly does work well enough it's not worth the investment to make a change, at least for me. But I fully understand why someone would change them, especially like in Nick's case where he hauls alot of local loads at lower speeds.