I find it way too difficult on the default difficulty(Advanced).
Either that or I'm really shit at the nuances of career because my first fight in the UFC I was 11-0 against Ross Pearson and got KTFO in the third round because I was like 15 overall lower than him and was in the high 60s in almost every stat. Couldn't do shit.
The trick is to boost one thing super high really quickly, then bring the rest up while you win fights using what you're best at. Trying to be well rounded out of the gate will get you beat.