As someone doing their first serious Forza 5 playthrough since the economy changes made at launch (and loving it), it's even more encouraging to see developers recognizing the concern to the point of excluding those transactions completely [Article by Emanuel Maiberg (@emanuelmaiberg on Twitter & Google+)]
[Edit] I think SeanSpeed summed up an important point about this development:
Forza Motorsport 5 launched with an in-game economy that many players complained made it too hard to obtain all the cars in the game without spending real money. Developer Turn 10 Studios has since made "fundamental improvements" to the game, but Playground noted fans' reactions.
As Playground previously announced, Forza Horizon 2 will not have microtransactions at launch
[Edit] I think SeanSpeed summed up an important point about this development:
The main problem that can come with microtransactions is if a game's progression is designed to heavily encourage the use of them. But if a game doesn't even have them at launch, its likely it means the game will play just fine without them.