I think the thing that people are underestimating here is Pedro Morales and his toughness. Pedro wasn't just a scientific wrestler. He was known for having a "temper" and would often let loose on his opponents when the heels "made him mad." Basically he would "Hulk up" or go on the "Warpath" in his matches and throw all of his scientific moves out the window and just start beating the crap out of a guy. Basically, he could be tough and could fit in an ECW styled match. Obviously he didn't have experience using chairs, tables, ladders, weapons, etc. but that was due to the time period and territory he wrestled. They didn't exactly have barb wire, inferno, and TLC matches in the early 1970's WWWF period.
And Pedro had incredible stamina who could wrestle very long matches, something that Steiner never really did. I don't think Steiner ever wrestled a match longer than 30 minutes, not even when he was in his prime as a member of the Steiner Brothers in the early 90's. If I'm wrong, please correct me. Pedro on the other hand wrestled a 90 minute match with Bruno Sammartino at Shea Stadium in the early 1970's, and while it was pouring rain I might add.
He was also ridiculously over with the crowd, so he would definitely have the fans on his side in this match.
And another thing is that everyone here is selling Pedro WAY SHORT on his drawing power. He was WWWF champion for two years, so if he was champion that long, he must've been able to draw pretty good. I think there's this notion now (as has clearly been shown by the posts made in this thread) that Pedro was a terrible draw who wasn't over at all, but the simple fact is that he could draw, just not as well as Bruno. It's much like Macho Man and the Ultimate Warrior compared to Hulk Hogan. Both were good draws, they just didn't draw as well as Hogan. Same deal here. Pedro could draw, just not as well as Bruno could, which is why Vince Sr. wanted Bruno to come back.
Frankly, the only real advantages here that Scott Steiner has over Pedro is his mic skills and moveset. Scott was better at both fronts, but really that's it. Scott is more well known to modern fans, but when it comes to legacy and achievements Pedro is ahead of Scott Steiner. As has been stated he was the first ever Triple crown champion in the WWE, won numerous titles in other territories, and was the WWE champion for two years, meaning he had one of the longest reigns ever.
Pedro, for me, is the clear choice here. Kayfabe or not.