Hey, I felt the same way about the game, but now I just can't wait to get rid of it. I'll explain why.
First off, I found this game by being an avid LBP player/frequenting LBP's community stuff. I thought "No way, create game based on racing? Mario Kart will be dead!" That's how it was for me when I first got my hands on it 5 days ago. :/
Career
The first tour in the career was easy (lulz understandable since it was mostly tutorial). So I flew right through all of those getting all tokens/challenges in my first try on the course, or a second try after learning the course. The second definitely kicked it up a notch with all those "boss" mods that you have to face on the courses. I thought it was interesting how the whole grudge match thing played out too. ;D Fun...I thought.
Next came the Grim Tour (3rd I believe) and I was having fun in the first two races, albeit the difficulty definitely kicked up even higher. Modobahn...oh man. I hated that challenge of hitting one person with the devestator. What a bunch of BS. First off, the opponents don't even go under them, and second, you have to come in first after waiting back for most of the AI to catch up. I eventually got it after I'd say 70+ tries on the course. :| Challenging? No. Luck Based? Yes.
Now I'm at the one challenge of sideswiping the Luchador boss (Dolor) while in a small little village area on the track. Sounds easy. Right. The only problem, Dolor tends to stay back in 10th-12th place the whole race, and so likewise, you have to hold back too just to hit him. Once you do hit him, he becomes godly at racing and TELEPORTS (yes, he teleported twice for me without Warp) into 2nd-1st place causing you to have to play catchup for the whole race. :| I managed to almost come in first, only to be nailed with four level 3 weapons on that last turn to the finish...
The career challenges and AI boss characters are rigged I say. Causes too much frustration for what it's worth and is causing me to strongly consider returning the game (also Nato's bomb challenge is BS too).
Create
Now this is alright I guess. I just feel however that I'll make 5 pretty good or awesome tracks, and no one will look at them. So in a sense, I just wasted time. :/ Besides, the controls for the create are pretty clunky and annoy me sometimes. :P
[/end super rant] Had to get that out. Frustration >> Fun in this game.