I'm really failing to understand as to how you see this as a positive perspective to the racing series?
It's because it's a good thing. And it's a good thing because it takes away nothing from realism, it can provide very serious sim racers with an additional tool to improve their experience, and at the same time it can be used by less experienced drivers to help them develop their skills.
You're looking at it as some kind of pure arcade feature, but does that really make sense?
See below
The game is meant to implement as best as a driving simulator as possible, how is giving the series a negative feature going to help make it any better? I say if you can't run the perfect lap then DEAL with it and try again next time. That's what the free run is for and that's what practicing in your OWN lounge is for. Keep the arcades away from the simulators, make them easily distinguishable. If I want fun I'll go to nfs for that. If I want a simulator I'll always have the gt series to look forward to. (FOR ME, seeing as I don't have the greatest computer and I don't want to switch consoles just to get a "better" gaming experience.)
Then what about professional drivers? They don't just "deal with it" when they are uncompetitive. They use tools outside of practicing on track (which they sometimes can't do anyway) to improve. Simulators, engineers looking over tons of telemetry, manufacturers refining the design of the cars, etc.
It does not make sense to say that all you're allowed to do is free run laps to get better, not when this is a sim. Rewind isn't necessarily a direct analogue to real world methods that drivers use outside of the track (though it very easily can be since reversing time is easy in physics and hence easy in a simulator - and there are simulations that run in reverse time, usually trying to reconstruct initial conditions from final conditions) but it does a good job of mimicking the impact of those tools.
I have no idea what you're talking about with NFS vs GT. When I want fun, I go to a simulator because they are usually more fun than arcade games. This is why I prefer GT over NFS. And of course realism should only be judged based on the maximum amount of realism. If some has arcade features (and SRF is really the only one - even if you want to include rewind as a hypothetical feature) but you can turn them off, then they don't matter from a realism perspective. It's when you can't turn them off that the realism of the game is harmed (lack of roll over in previous games leading to wheelies, etc)
**edit**
As for the whole "SRF is or bragging rights/I'm a better driver than you". The hell it is, how do you feel when you jump into a room with a host thats permitting tcs/asm/abs andyou win the race WITHOUT using the aids. How is that NOT bragging rights/proving to the grid you're a better driver. It's the FACT that people get so used to using the technological aids that they begin to rely on them. Let me repeat the wonderful quote from one of the worlds finest race drivers ver to live... Ayrton Senna
Firstly, it's far from fact that people get addicted to driving aids and simplifications. I started GT1 with auto transmissions, but by GT2 I was using manual. GT3 introduced global driving aids which I left on at the start, but then turned off. By GT4 I was turning off aids whenever I bought a car. You can also look around the forum as you'll see multiple threads from people asking for assistance in going from auto to manual, ABS on to ABS off, SRF on to SRF off, etc.
Secondly, when I win in a room that allows TCS and whatever (I have never used those things in GT5) I don't care. It doesn't matter. The use of TCS have nothing to do with driver skill and TCS is just about everywhere in the real world. SRF is a different story since it's basically non simulation, but everything else is perfectly fine. I don't really like it when people insist that difficulty is realism, that's just stupid and often leads to less realism.
I was actually racing online in Forza the other day in a room labeled "Full sim". This apparently meant that you had to use clutch with manual for all cars, even cars with auto transmissions. That clearly isn't quite accurate to real life, but some people insist that that is "simulation". The same is happens when people complain about TCS, or look down on rewind.
Long story short, people brag and act like they're top notch with driving aids (personally speaking from witnessing this first hand) and then when you ask for fair competition and ask them to turn it off, they act like you're holding them at gunpoint and then you get kicked for a small yet fair request.
Allowing aids in the first place was fair. If you're asking that they race with everything off, you're probably more likely asking for something to stroke your ego. SRF, even as the arcade feature it is, is fair as well. If someone wants to concentrate on becoming a skilled SRF driver, that's perfectly fine. They have no obligation to learn the game with simulation settings.
NO I'm not saying that EVERYBODY is going to turn into this horrible conundrum, but you simply cannot deny that this is going to happen more often than not with the rewind feature, It can't be tempting to use if it's simply not there to begin with...
No, rewind probably won't negatively affect anyone. Very poor drivers won't be able to use rewind as a crutch. What they can do it use it to use it to increase their repetition with certain situations and then improve faster which would probably lead to them using it less in races. Though I guess it also depends on how good they want to be at the game in the first place.
Then of course you'll naturally have those people who will want to win under the most difficultly possible and they try racing without rewind and whatever else naturally, by themselves, just like with manual transmission, TCS, SRF, whatever in every other GT game.