Well, the poll question asks: "In your opinion, do you think Project Cars can be considered a *true* sim?"
As for realism in terms of grip.. which is worse: 5% too much grip or 15% too little grip?
Objectively the answer is obvious.
Also, the confusion is in the
progressive grip level of the tires. Especially the street tires are massively progressive in their longitudinal grip levels.. too much so in my opinion. However, actual PEAK GRIP levels of the tires seem pretty plausible and are extremely close to the other simulators like iRacing and Assetto Corsa (which has the highest peak grip on default grip levels of all the tracks).
Traditionally the actual progressive grip levels in sims have been awful and nothing at all close to reality. Not sure how many of you guys here remember iRacing's old tire model. It's a great example to make every single time these things come up because the consensus among most self-titled "hardcore simracing" people was that iRacing was the most realistic simulator ever. Only a few brave souls dared to oppose this notion on the old iRacing forums and said that rFactor, GTR2 and Live 4 Speed were far more realistic.. among these quite a few real life racing drivers. Of course these people were heavily antagonized and ridiculed on the forums.
.. fast forward to today's iRacing version: Tons and tons of more progressive grip and tires that are far easier to drive. Tires that make a whole lot more "sense" and actually behave like real tires.. somewhat.
Not sure the "it should be difficult to drive! = realism" thing will ever truly die but it's always good to remind people of checking reality every once in a while. You have all the tools necessary to see if something is completely off or somewhat realistic. Heck it's usually enough to look at the G-force readings to see if we are in true-arcade territory or lunatic-fringe-ice-racing territory (luckily there doesn't seem to be a single sim alive in this category any more).
I've only ever driven various kinds of street cars so I have no real world experience of proper slick tires and such but at least the street cars with the Masculine Allweather tire in pCars is pretty damn convincing until you do silly stuff.. and even while doing silly stuff it's almost there, most of it falling apart due to the car setup having been tweaked for console players. Simply changing the differential to a more appropriate and realistic value transforms some of these cars. Sure, they are not "perfect" yet and probably never will be but in my opinion they are as close to reality as any sim has ever come yet.. except for the issues with longitudinal grip levels that do annoy me (or "transient grip", when the rubber suddenly twists and regrips). That's an area AC is superior.. but then again the AC street tire models fail in other areas like how they can feel real strange during minimal understeer moments that just "explode" into random weirdness.
I'd also go as far as stating that the GT3 class of tires are extremely believable but this is of course pure speculation on my part as I've never driven a GT3 car and probably never will.