Already in Victoria 1 with the inventions the impact of player on technology gain was much less than in comparable games and more realistic. I agree that the triggers for inventions should be more advanced taking into account more factors than just year in MTTH
Perhaps having a higher chance to fire if neighboring countries already have that invention? Additionally, countries with Laissez-Faire governments could have a higher chance of getting inventions than countries with interventionists governments, since Laissez-Faire promotes competition, and thus entrepreneurship and innovation.
I certainly hope they keep the inventions for Victoria 2, though. They're pretty unique.