He's too heavy. That was/is his downfall. If your main weapon and fighting style is striking, you can't keep making yourself heavier and heavier like it's a good thing. All that muscle is useless when you're tired, and because of them you're getting tired fast. And since you're not fast enough even when you're fresh in the 1st - you're not getting that KO before you're gassed. And that's what we saw.
Alistair recently stated that he's gaining weight. He should get down to at least 250lbs or he will be getting KOd in every second fight.
Cain would demolish him right now.
You gotta be able to adjust to your opponent during the fight and have a plan B. Fitch never seems to have one.
This looked exactly like the Penn fight, where he wasn't expecting to be taken down and had no response for it... until the 3rd when it was already too late.
The only advice his cornermen were giving him was to not taken down and outstrike Maia (what, ironically, with Maia's improved striking wouldn't grant him success). What he should've done was to impose his will, take Maia down and be on top of him doing damage. The fight was going to the ground anyway, so he should've make sure that it's on his terms not Maia's.
But since his plan to was to strike with Maia, he kept doing it even if it was clear that it wasn't working. And so he let Maia dictate his own strategy.
It seems he was not motivated. After chasing the title for so long, Nogueira might have felt like not a big enough challenge for Rashad to get motivated. And we know he's not beating Jones, ever. So I think he should consider dropping to MW, where he would start anew with new goals in mind. I also recon he neglected his wrestling a bit, thinking he is a (kick)boxer, which he is not.