The career system has been a big focus for the devs. There is no point in trying to cram as many cars as they have into the game, across so many different serie and types of cars, without a structure to the game. So what they have been doing is looking at the career mode as a development, not just a random collection of events like FM4 was (I don't know about FM5, I don't have a XBone), with a properly defined system of tiers, and the progression through those tiers that require certain standards of driving. For example, to move on to Formula Gulf from Formula Ford, you must have either finished in the top three of the championship, won three races, or prove consistently high qualifying and race performance, and have raced cleanly without crashing into people. Whilst going through the career, you have the option of staying within the championship you have just competed in, moving to another championship in the same tier, or dropping back and trying another kind of racing, all dependant on the meeting the performance criteria and the offers that you get from the teams.