The game simply should not be altered in such a way just because some people feel like they should be able to have 1000 cars in their garage at the beginning. It never has been that way nor has any other game of the sort and it shouldn't be. I would also venture to say that it won't be.
So in other words, you think the fans should be ignored? That would include you.
It never has been that way. In 2005 it never had online. In 2000 it never had PS2 level graphics. As of now it's not a game on next gen consoles. Let's hope PD never changes this. "It never has" doesn't justify anything. Neither does what other games do, but I'll say that many games have done this already.
You also like to keep mentioning that you think GT6 won't allow import. This doesn't support your opinion in any way, nor does it make anything else you're saying more correct.
Of course it changes things drastically. No need to earn credits if you already have 1000+ tuned cars in yoru garage. You already have the best car for every event and in many cases upgraded as far as it will go with RS tires making most events far easier than they should be and down right boring. Online it would be a huge advantage for those that imported their garage compared to those who did not. Surely you can see this, it's not rocket science.
Indeed it isn't. Credits are just grinding, so taking them out of the picture does nothing to difficulty. It just saves time. Car selection won't change difficulty either. With GT as is, if you wanted to make a race easier, you just grind (you can come in last place every time if you want), then you go buy or tune an overpowered car, and then win with ease. On top of this rules might make it so there is no best car, or that tuning is impossible.
Online is where the advantage is even smaller since hosts have tight control over rooms. Also, if there was an advantage for people who imported, that's fine. The people who did not import would have chosen their path. They would have chosen to be an a disadvantage online, and that is perfectly fine.
In addition it would also prompt people to import that don't really want to just because they may feel the need to do this in order to compete online and thus ruin the career mode for them completely.
You would only import if you didn't want to do GT Mode in the first place. Even if that wasn't true, it's still your choice to import, so again there is no problem here. What is a problem is that if import isn't added, people who would like to use the feature would be unable.
The right way to play is the way the game is designed to be played.
No, there is no right way to play except how the player wants to play. There isn't a single reason to think otherwise.
If players don;t like to play the way a game is intended to be played then they should play something else.
Just as valid is fixing what's wrong with it.