There are so many criticisms made about this game on these forums, some justified, mostly not, IMO.
R* themselves come in for a hell of a lot of abuse, but I've come to the conclusion that the one single element holding back GTAO back more than anything else at the current time is all the crap, ramp-infested user-created races and tedious 10000000RP etc etc knife-only deathmatches. Getting into proper races and death matches takes ages because of this sh*t.
The easy way to solve this problem is to remove the content creator. It's simply not adding any value to the game and is in fact having a negative impact on the whole experience.
Users simply can't be given tools like this because the vast majority don't have the wit to use them properly.
EDIT: Had an idea halfway through the thread which would solve the problem...
R* could add a blacklist option at the end of each job. If you choose to place a job on your blacklist, you'll never be put into that job again. The blacklist could be editable in the options to you could unblacklist jobs at any point if you wanted to.
That would solve the problem without pissing off the people creating proper content.