Was Ali considered a big HW when he debuted in his time?

Well, yes. Outside of Terrell, he was always the bigger man earlier on. Williams was pretty big, too.

Later, Foreman, Lyle, Norton, Bugner, and a couple of others could physically match him.

 

Fairly big yeah - but wasn't seen as a powerful wrecking machine like Liston or Foreman.

 

When Ali debuted he was 192 pounds. That's the thread ask.

No he was not seen as a big man when he "debuted". He'd been fighting for 6 years and was 20 pounds heavier when he fought Terrell and Williams. He debuted as an 18yo.