I have the Deluxe Edition (and I assume many others so as well), so the DLC doesn't really affect me, or at least I paid for it upfront. But if this game gets Season 3 and even 4, the amount of DLC available alongside the game will leave a poor taste in new player's mouth. While the game is on sale, the price of the DLC is nearly equal to the price of the base game, which is ridiculous.
When in Season 2, the price of Season 1 content should be permanently 50% off. When we go into Season 3, same should happen to Season 2 and Season 1 content should become free. This way, DiRT Rally 2.0 becomes a better and better package with time for first-time buyers and the price of the paid DLCs remains the same at all times. It also shows a commitment to further support the game with more updates and more seasons.
Lets be honest, most of this content was already finished before the release and is waiting to be put behind a paywall. A ton of negative reviews on Steam mention the DLCs and, given that it's the only thing potential buyers can actually check and see (by looking at the amount and price), it works as an immediate deterrent.