At the moment I'm not terribly interested in either.
I'd say this is where I'm at as well. I didn't like Forza 7, but I can at least see the merits and the point of the Forza series as it is now that it is on a platform that generally never had a game like it or GT, and I'm not exactly that keen on seeing T10 take the wrong message from a group of people who just want *another* hardcore sim racing game so that they can justify the purchase of their wheels and sim racing set ups, and use it as a beating stick against those who do not have the money, or space, to indulge in such a thing.
However:
And as far as GT goes, PD haven't shown they can design a game since they patched standing starts out of the already questionable GT5 to make every race into catch the rabbit nonsense. GT6 was so bad, and so much worse, that I dumped it on Craigslist after a month; and only rented it again a year later when I wanted to see if they actually had cashed the checks their mouths had written regarding the course creator (which, lol of course not). PD's going to have to do a lot more than turn on the applause sign after showing that they can recreate the GT4 interface in higher res to get me to commit to the PS5 ecosystem.
This is all bang on. The fact of the matter is that I've seen since GT Sport's release, on this forum specifically, that Polyphony can do no wrong, that Sport mode is the greatest thing since sliced bread, and that Kaz is both the second son, and the patron saint of the racing genre. All of these are gross over-estimations, and within GT Sport specifically, all it has done is mask the problems that the GT series as a whole has had since arguably GT4: the single player, AKA the main mode that 90% of people are going to play up to GT Sport, is crap, and follows the very same mould that by this point, has been stale for as long.
Chasing the rabbit scenarios in racing games are not fun. They never were. They're especially not fun when the AI within them have absolutely no give or desire to be anything but a yardstick for the player to pass for an easy win, and the only time they show anything that isn't slavishly sticking to the racing line is binning it with more regularity then is probably needed. That's all GT Sport's laughable single player suite is - continuous chase the rabbit scenarios, and the fact that this was supposed to be the saving grace of the game after Kaz told people to go **** themselves and take an effectively always online game and not complain, is especially hilarious. I don't think there has ever been any actual challenge in a GT game, not especially in any GT game since 5 - really, it's just been making sure that AI are spaced out far enough from you starting at the back of the pack to make it harder for you to just waltz by in your supercar, or world beating GT-R that makes mincemeat of anything thrown at it.
That comes into play with the trailer with GT7 too - aside from the forced and cheap pops of nostalgia for GT4 that you allude to with the single player interface, what was shown that is actually going to get at the root of the problem with the GT series, that the main mode is not fun and not challenging in the slightest, and doesn't even do a good job of preparing people for the online racing made mandatory with GT Sport, considering the game's rampant problems with regards to ramming and dirty driving that is supposed to be alleviated with watching three minutes of moronic good etiquette videos that nobody actually takes anything from? I get that it's early, but these have been problems since GT5 at earliest, and especially came into the fold with the jury rigged single player portion of GT Sport. And yet...the circlejerk of Kaz being a patron saint for adding on a ******, boring single player suite for free persists.