I wouldn't worry about GwG, people are used to "try" the GwG titles, don't like them, uninstall, forget. Those people won't play the way long enough to get angry about it.
Let me tell you about my 2 worries for SMS:
Reviews
Most people seem to think that metacritic scores have become less important in the last few years and personally I think that only holds true for mediocre review scores of games, where people see what they are getting anyway: Fallout 4 for example, you played 3 and NV and Skyrim, see the screenshots of 4 and some minutes of gameplay, you know what you're getting, feel the itch and buy it, if review scores aren't abysmal. Other example where review scores used to matter are the unknowns that have fantastic review scores, but these days prices fall so fast and backlogs are so full, there is much less of a need to jump on the secret hits right away.
Where review scores still matter are niche games that can give the average guy that itch, that "wow, that looks awesome... and you can do WHAT in that game?! Fuck yes, I need that!" feel. If you have that itch
and the reviews are full of praise, then the day1/full price buying chance is still really high even nowadays.
Project CARS can scratch that itch with the sound, the weather and the lack of games that filled the Gran Turismo itch on PS4 (good single player campaign needed though).
Project CARS 1 had really good review scores, but I always felt that many of the reviewers thought of pCARS1 as this super hardcore thing that is just not for them, but that is no reason to give it a bad score if it's for other people. Bigger review outlets have reviewers who know their hardcore racing games, but most probably don't have people like that. Many must have seen pCARS as this refreshing hardcore alternative to GT and Forza, which both didn't look great to the average reviewer at that time (Forza 5 more of the same in better looking but low on content, GT6 lost in the past). Project CARS had the fantastic sound, the lighting and weather and an insane amount of tracks, if you were good at this game, how could you not love it. Just because you as the reviewer suck at it doesn't mean that it's not great for others who
are good at it.
Now to where I see the problem: Reviewers have seen other hardcore racers like DiRT Rally or Assetto Corsa, the novelty factor is out. And what if the reviewers will have new GT (it looks fantastic, sounds already better, will probably control really well and what if the online play is as great as it's supposed to be; it could be killer) and a new Forza (probably over 600 cars and developed with Scorpio power in mind, also reviewers seemed to really have liked FH3).
Another factor for review scores is the performance and reviewers seem really fed up with games that have framerate/-pacing issues these days. Had pCARS come out now with how it performed on XB1, reviewers would have banged on framerate issues much more than they did with the back-then prominent 900p issue.
Date
I think the release date of pCARS 2 and those of other racing games will have strong effect on sales. Unfortunately I don't really have a clue what will be the best scenario. It depends on how good it is and what it has to offer compared to the other games.
Scenario 1:
- pCARS 2 out
shortly before Forza and GT
people will probably wait, price will already have dropped, less day1 money
Scenario 2:
- pCARS out
shortly after Forza and GT
- Forza more of the same as 5 and 6 and GT low on content and people angry about online focus, pCARS 2 looking good and gets good review scores
pCARS2 will sell a shit ton of copies
Scenario 3:
- pCARS out
shortly after Forza and GT
- Forza back to FM4 greatness and looking amazing on Scorpio and PC and performs well on PC too, GT with some really good SP content and looking and sounding amazing, online works and gets great word of mouth
It won't matter if pCARS2 gets good review scores, it won't sell well and people will wait with their purchases
Scenario 4:
- pCARS out long (6 months+) after Forza and GT
- Forza back to FM4 greatness and looking amazing on Scorpio and PC and performs well on PC too, GT with some really good SP content and looking and sounding amazing, online works and gets great word of mouth
Average players might be ready again for a new sim'y racing game, but there will be GTR3 (raceroom sound + Unreal 4 graphics) and maybe a new GRiD with graphics from the Evolution guys on the way that people might wait for.
Either way, it's tougher out there now, especially if you rely on selling over 1.5 million copies in the first year again. An Assetto Corsa and even DiRT 4 have the advantage of being profitable much earlier (AC with less employees and DiRT4 with Codemasters with probably 4 titles in 2 years =less risk per title)