See I find both Hakone and Grand Oak both frustrating exercises in understeer management. At least Rio had some elevation change and some genuinely interesting corners, some of which remind me of the Baku street circuit. In general though whoever is doing track design at Turn 10 needs to seriously consider including some proper chicanes and tight corners, and back off on these dreary, endlessly long sweepers.
I fully agree with the last sentence in regards to the Camino to Dubai run of fantasy tracks we had in the previous games, and I had the same thoughts when I saw both Hakone and Grand Oak for the first time. While they look like they are from the same school of design as the previous set, they race 100x better than any of the previous run do.
I thought Hakone in particular looked awful from the preview and the intro race in the Cadillac didn't help much. After running it for league racing though I've found it's one of the raciest locations in the game. Hakone Club is fantastic in things like touring cars because every corner has multiple lines, so it's basically "ol' switcharoo" city. The full layout of Hakone is just okay, as the 2 right handers off the back straight are pretty single line so there is less potential for crossovers but that can also calm the racing down a bit which isn't always bad. The Club Reverse layout is more technical, but pretty awkward and invites more clumsy moves so races tend to space out more there.
The short version of Grand Oak isn't very good as T1 is basically the only passing opportunity, but the regular full layout is quite good. Again, multiple lines through several corners that either mean a move can be made, or a setup for a move at the next corner. Some elevation change, and the banking through T4-5 (or however you want to count those corners, I think the game counts them as T3) is satisfying to lean into and nail the exit onto the straight. The reverse version of the full circuit is still alright, but a few of the corners get a bit more awkward so I found it doesn't quite offer as much side-by-side racing.
I'd probably add Maple Valley into the terrible boring sweeper category but it was from FM1 instead of the Camino to Dubai run. Strange/sad that Maple Valley was the worst of the FM1 fantasy tracks yet it's the only one we have had prior to Sunset Peninsula returning. It's absolutely understeer city (the intro race with the Corvette E-Ray was painful), and it's also loaded with trap corners that bait people into awkward contact and/or off-track excursions that space the racing out.
Bernese Alps is probably the best, or rather,
worst example of the boring sweeper places though. It doesn't offer much in the way of alternate lines unless you are cheesing track limits, so while the high speed sweeping nature initially feels suited to high downforce cars and they are more fun to drive there, they actually provide the worst racing around it. The only time you really get much passing there was with low downforce or low grip stuff that required more finesse to keep on the line, but then you end up with the understeer struggle you speak of so it's even less fun to drive.
Rio was very fun to drive and hotlap but was pretty awful for racing. It required both fairly high skill and high patience/racecraft to have a decent race there. Most of the time it was just survival, and there several spots with abrupt stops if you hit the wall, not a good recipe for close racing. I always thought of it as Forza's Macau; a cool idea, interesting for qualifying, but dangerous and pretty much always bad to race at as it always ended up with a pileup/track blockage.
I think the only track from the Camino to Dubai run that was any good for racing was the Dubai "City Circuit" variant. It actually worked good for touring cars, but definitely required good car control and smart racecraft as it had a few trap corners that would bait people into make bad moves and crashing which spaced the field out.
I suppose it should be noted I'm judging them off multiplayer with people who actually have racecraft (and some who don't too of course) though. It doesn't seem like the AI really use alternate lines very well so tracks like Hakone Club definitely do not shine against the AI and I could see them being a far more dull experience. They also don't go very well with the low skill/IQ drivers in public lobbies that can't hold their line or set up a move properly. Using Hakone Club as the example again, I've had both the best races I've had in FM8 (probably
any Forza Motorsport game for that matter) at that track against good drivers, and some of my most frustrating races there with morons in public lobbies that just dive up the inside and understeer into your door and push you both off track.