In the comics, he's seen as peak human, but if you put everything together, it's kinda nuts. Yes, I know it's still "comics".
But look at these feats:
- Leg press 2500lbs for reps. World record is 3000 for one rep.
- Benches 1000lbs for reps! I think the World Record is 1400 for one rep.
- He barely sleeps, on purpose. And still is able to handle his superhero duties. Most people need 7-9 hours of sleep per night. Cognitive function is compromised if sleep deprived for a few days in most people.
- Master level of dozens of martial arts.
- Parkour expert, gymnast, ninja arts
- Intellect wise, he's just shy of Lex Luthor, and a genius in various fields basically.
Not to mention all the wear and tear he's taken. Should be in a wheelchair. But nah.
So what makes him superhuman is really the mastery of all these. In reality most people cannot be so well rounded since many of these feats require years of specialization. But Batman clears these with ease.
Amanda Waller sees him as meta human as well.