Originally, Noll let the QB call his own plays (that may have changed later when he had duds like Blackledge, Woodley, Malone etc. Bradshaw had the autonomy to throw all day long (and he often abused it in later years, heaving picks galore). Little doubt that Dan would have the same when his talent became undeniable. Dan would have done even better than Bradshaw in that sense, his velocity and release were close if not better than TB’s, he had similar chutzpah, yet didn’t hold the ball too long and take bad sacks like TB, and his accuracy was better (while he certainly threw his share of picks as well).
A couple problems were that the Steelers had held on to many of their old players far too long into the 80s. Some of the guys continued solid play (Stallworth, Webster) but many fell off. And other great vets who were replaced had unworthy successors. Miamis running game was not good but one with Frank Pollard and Walter Abercrombie would have been scarcely better.
Plus the defense was a sieve through much of the 80s, for much the same reasons. Hacks like Gary Dun, Steve Furness, John Banaszack and Tom Beasley manned the DL ridiculously too long. Lambert was a shadow of himself but went on until finally a foot injury did him in. Blount and Shell and Dwayne Woodruff were well past their prime but had no successors.
The QBs stunk in the 80s but were hardly the only problem. Miami had far better teams that decades around Dan.
And the Pgh media, led by assho1es Bob Smizik and Bruce Keidan, would have crucified any bad game, heck, bad throw, Marino made. It was these dicks who made up the drug rumors about Marino in the first place, remember. Imagine their vitriol had the Steelers still taken Dan despite their cautions. There would have been massive negativity over the team. You just knew that if Dan put up 400 yards and 4 td passes yet the Steeler D gave up 45 points, Smizik would blame Marino.
It wouldn’t have gone very well IMO