Yeah the whole time limited thing where you have to grind though some boring junk to get the new cars really shouldn't make its way over to Forza Motorsport. For a game that seems to have some interest in improving its multiplayer stuff, time limited, locked cars cause unnecessary problems for multiplayer modes, both on a public lobby level and at an organized league level.
I know I've harped on this several times before, but as someone who has been running organized racing (both as a competitor and organizer) for nearly 20 years now, it's a pretty big deal for what we do, for both the organizers and the competitors.