Yeah... If it's the TTV6 that's similar to the current GX550, it would be enticing...add a hybrid motor to the powertrain and I'm even more interested.In this hypothetical scenario, I would need to know:
1) LC300 Power plant for US consumers
2) MSRP and invoice
...but, the only way I'm choosing a 300 over the 250 is in a "price is no object" scenario, and that's not my current reality. I'd go as far as to call it a fantasy, but I'm happy enough with the 250 that I don't even really fantasize about owning other similar vehicles, such as a 300 series.
So, ultimately, my answer to OP's question is probably "The LC 250"...
Here's the thing...if this was a reality where I had extra money (and extra garage space) for a "weekend vehicle", I'd honest rather supplement my 250 with a 70 series than switch my 250 with a 300, I will say that much...I may be off my rocker, but I bet if you pivoted this question into a J70 vs 250 scenario you would get a much less divided consensus. I was in Yokosuka last month, and will be going back next year. I would spend wayyyyy too much money to get my hands on one of those 4 door trucks.
...but, no matter how sexy the 70 series may seem (at least to someone like me who loves the utilitarian aspect of it), I know that I wouldn't want to rely on one as my sole daily driver either, as I've grown to used to modern comforts... so if you posed this question as "would you choose a 250 OR a 70 series?", I'm still going 250...but a world where I could own both would be awesome.
and yeah, whenever I see posts suggesting that Toyota would sell a ton of 70 series if they brought them to NA, I have to disagree...for the reasons stated above, I think that initially a lot of hobbyists and enthusiasts would initially buy them, but otherwise interest would be VERY limited; there just aren't that many people who want to drive such a utilitarian vehicle, or that can financially and/or logistically justify keeping one as a "weekend" vehicle, IMO.