I like PP for one reason, it provides the best and most fair racing in my opinion. I don't mind tuning cars, but I don't spend countless hours tuning my cars. I'd just rather not find a 600 hp room, enter, and get passed by all the wing equipped McLaren F1's which have a clear advantage (true story).
I'll allow that you may be right when referring to PUB LOBBIES & restrictions.
I see what you mean, believe me.
But I'm talking about organized racing.
I gave up on ALL pub lobbies except Shuffle Racing & NASCAR ONLY, almost immediately after trying random pub lobbies.
As far as I can see... racing in pub lobbies 👎 It's problematic from the get-go to the finish line. A complete waste of time for me.
It's also absolutely devoid of any really interesting road car racing I'd be interested in. In pub lobbies, no matter what the room is labeled, it always turns into people bringing super cars or at least the Lotus Elise, or demanding that the PP limit be raised, again & again. That's how it goes.
Those of us who want to race the more unusual cars are unlikely to find anything in pub lobbies.
Because in pub lobbies, people only race the most competitive cars at any given pp... or in any given class for that matter.

People in pub lobbies seem to ignore 80-98% of the cars available in the game!
And that's just my complaints before you even get into the dirty driving tactics issue!!!

And how hard core gamers in pub lobbies know how to exploit the damage system, the penalty system, to their advantage.... etc etc.
And of course there's invariably some unsupervised child or someone with a mental problem who's likely to join at any moment & spoil things.
NOT a good situation if you're looking to MAXIMIZE your playing time.
For my interests, and the cars I want to race & the type of racing I'm interested in...
Pub Lobbies = Waste of Time
Limit one, have all drivers enter, then set the other limit while everyone is on track. Those cheating get kicked. You don't need honesty.
I already thought of that. And there's still a flaw.
As a host, I'd rather everyone could be 100% sure that *I* am not cheating too.

I wouldn't... but I don't want anyone to have any doubts, especially about the host!!
Using PP - find the best suspension, gearing.
Non PP - the above but in addition: find the car that allows the most downforce, gets the flatest powerband, and has the best chassis. -> Way more exploitable.
Again, we're talking about apples & oranges here.
You're talking about free car choice pub lobbies.
I'm talking about organized races with very specific car restrictions. Say, restricting to one class & banning outliers (the turtles & the hares). Or 1-make races (or 2-in-1 make races like the one I'm currently organizing). Or organized races with a very specific list of cars that are allowed.
When you're dealing with this type of racing, there's a lot less to worry about in terms of gearing under the hp/weight scheme, so long as the cars are not at maxed out.
Then it just becomes a matter of some quick tests with the transmission at the hp/weight limit... some adjustments on the suspension & LSD (that you might even find a set-up in the Tuning Section of the forum - which you can try out to see if it works for you, without ever having to start from scratch). And off you go.
No fussing with seeing what PP the power band is best at. You know what you're in for, you might try adding or taking off parts, but otherwise, it is what it is, and you set your transmission accordingly. Process complete.
Thirdly, tuning is not cheating. I don't know why you're so against it. If you're losing because you can't put in the time to get better, that's not a bad thing.
I'm not saying that all tuning is cheating.
But I would rather lose because of poor driving skills, than win because I have some great mechanical advantage trick I know and my opponent doesn't. So in that sense, yeah, I would see it as cheating... If I just win because I have a faster car, because someone couldn't spend an hour tuning & analyzing their power band, because they had to make dinner before the race... seems rather dull & stupid to me.
I'm not saying YOU shouldn't tinker with the power band and race in PP races if you enjoy that.
BUT I DO NOT. And I think that should be OKAY too!!!!
Not have some smart remarker tell me "learn gearing"

I don't think you would appreciate it if I told you that you should play the game in only stock cars from the recommended list and stop tuning!!!
So don't tell me I should play your way!
That's my point.
You should NEVER assume your way of playing this game is the right way.
Because believe me, after seeing the NASCAR ALL day series... I realized that "clean" means different things to different people, even on this forum!!!
Not saying it's wrong... Just saying that people have different ideas about how to race.
(ie: I'd seen cleaner random NASCAR pub lobbies than the GTP NASCAR lobby today. LOL)
Fourthly, you would probably do poorly against people who spend more time playing if there was no tuning.
I would say that's half true.
Only half, because people who spend more time playing, also spend more time tuning.
But of course, that's why I like highly organized hp/weight restriction races, where suspension, LSD, & transmission tuning is allowed.
I'm not so against tuning altogether.
But not complex PP tuning. It just amplifies the times I have to re-enter the track to run another timed lap test...
And I don't want to be studying graphs or making spreadsheets. I just want to set the car up, do a couple of test laps to check, and then race race race!!!!
Speaking of which, having lounge/lobby free run work like "practice mode" would be helpful too.
One of the biggest time wasters in GT5 is having to do an off-lap before getting to a timed lap in the lounge/lobby.
But unfortunately, I've found some cars that do behave differently in the lounge with the same settings as practice... so I think it's safer to tune online.