His cardio isn't crap but it isn't great either. He slowed noticeably after the second round- right around the same time he stopped smiling.
Win, lose, or draw against Pettis, I think the time is right for Aldo to make the jump. I really believe 155 is the best weight class for him. There's not much left for him to prove at 45 and the list of viable, interesting fights is dwindling fast. If Frankie Edgar was too fast for virtually everyone at 155, can you imagine Aldo at that weight?! Couple that with a theoretically improved gas tank and he's real scary for anyone in that weight class.
It's just frustrating watching Aldo fight. He comes out the first 2 rounds like a killer. He pushes the pace, his striking is crisp, fast and accurate. Every round after that he starts fading and fading fast.