It's not apples to apples with this discussion, but at the Product Showcase event in Plano, I spent about an hour driving the LX 570 and LS 500 back to back... I wanted some seat time in both to think about what the next LX might be like with the TT V6, as well as a bit of a "goodbye" to the LX 570.
First, the '21 LS does behave better than the last one... the transmission feels more sure footed and natural, and it changes gears quicker when you put your foot down. However, the turbo lag is just as bad as the '18-'20 and it's pretty dead below 1,750 rpm or so. That doesn't sound so bad when you read it, but for example, Mike was next to me at a stop light in a Camry TRD and when it turned green, I had my foot to the floor but was looking at the back of a CAMRY up to about 50-60mph due 100% to turbo lag. As the LS builds RPMs, it hits its stride and you certainly feel the power, but it's not the same thrust or sensation I've had in previous LSs or other V8 sedans. A large part of that is the 10AT too - it's so soft and smooth that you don't get the rush of feeling gear changes and then power surges... the LS's power delivery is more like riding a wave: consistent, it build's somewhat slowly, and then you're suddenly going 85mph.
The greatest surprise to me was how slow and lazy the 5.7L V8 + 8AT are, especially in comparison to the V35A + 10AT. For everything I just said about the LS 500, the LX 570 is much worse, and of course it should be. I know there are many differences between car and SUV applications, but especially for the latter, the V35A is a vastly superior engine. Those upset about losing the V8 will be humbled the first time you drive a truck or SUV with the V35A... I am in that category, so here I am admitting it. You put your foot down in the LX and it takes half a second to think about what you just did, another half second to think about how it wants to respond, and then it starts laying down the power but in a 5,700lb SUV. It's pretty slow, and none of it is in any hurry.
The V35A having so much more torque and quicker gear shifts will be a massive change compared to the 3UR-FE in real world driving. We also know TNGA-F dropped about 450lbs in the Land Cruiser, so with the LX and Tundra, we're looking at vehicles that might weigh 300-400lbs less with a lower center of gravity, the powertrain tucked further and lower into the platform, a much faster shifting automatic transmission, 30 more hp and 80 more lb-ft of torque. It will be quite a change and I don't think anyone will miss the V8. I say all of that as someone who loves V8s.
The reasons I don't like the V35A in the LS are less important or obvious in an SUV or truck: power delivery and NVH. Most SUV drivers are looking for torque, but most LS people I know are looking for smoothness and silence. The V35A isn't as smooth as the 3UR, but it delivers a lot more torque. It also sounds more like a V6, but I think that's less of an issue in a truck or SUV than it is in a performance/luxury flagship sedan.
The one thing about the V35A that Lexus still needs to fix regardless of the application is the turbo lag. It's still very noticeable. Under 2,000 RPMs, the turbo lag makes the car feel sluggish if you're looking for power off the line. Again, I have different expectations for sound, speed and power delivery when driving something like an LS and something like a Tundra. For the Tundra, LX, Sequoia and Land Cruiser, I think it will be a massive upgrade over the V8. The LS still needs something different to provide the type of low speed smoothness and responsiveness that those owners came to expect over the years, and I personally think a hybrid (TT V6 + batteries) is just the ticket.