4th gen has stiff competition from the start

No doubt that the issue is in programming, not necessarily the fact that it's a 6 speed. GM solved a lot of their clunky transmission issues with more gears; to your point, the OEM's are looking to get more efficiency out of their transmissions and sometimes sacrifice how smooth things are.

 

Yep. My 3G is terrible with the cruise on, barely notice it shifts with it off. Tells me it is programming.

Being an automotive engineer must be a horrible job, since they are trying to appease everyone. More power, more efficiency, best payload, best towing…all the while the government and epa are breathing down their necks. Has to look cool too! Can’t make everyone happy…(ya know!?)

 

Top of the Line Off-Road Comparison:

 

That is just Toyota's cruise control programming in general, it is awful.
I drove a family member's 2016 4runner with the 4.0 and 5 speed quite a bit, and I would bet they use the same exact basic logic for the cruise control on that as they did in my 1996 Tacoma. They behave almost the same with how they handle hills and operator inputs.

It always waits way too long to downshift, throws the revs way up once it finally does, and hangs out in that gear after you've crested the hill/leveled out for a little while until it slams in a higher gear when it finally upshifts. Same exact characteristic for two vehicles separated by 20 years.