It may be the practice I've gotten, but I found Expert World Tour to be far easier than Hard Mode. I blasted through it in Expert in about one or two days once I unlocked it, clearing most events on my first or second try. Traffic Attacks excluded of course; those still took around an hour each other than the earlier ones. However, everything else from races to ring attacks were ludicrously simple. In fact, I started looking forward to ring attacks since they were so easy.
For those who are wondering, for most events I used Vyse with Acceleration mod which has stats 4/3/3/2, and for traffic attack I found that Amigo with Acceleration mod worked the best since he could move in and out of lanes without drifiting due to his high handling, coupled with the fact that his max acceleration will get you up to speed briskly.
Basically, don't give up. The game gets a lot easier with practice. Learn to drift a lot and get to know items too. Also, if you're having a hard time with certain AI characters, turn on another controller and make player 2 (and 3 and 4) the characters you're having a hard time with. Less AI to race against and less of the hardest opponents too. Good luck to you guys!