He's still recognisable as Quint over Rockman.
Do not forget that Quint is also Rockman, it is still technically correct.
But just to make clear what the intro story actually says;
Though without any witnesses, the one leading the Dimensions with overwhelming power was a robot like Rockman.This is the narrator speaking. The narrator has no reason whatsoever to bring up some obscure GB side series character at this point; it would confuse newcomers with unneeded explanations of Quint's origins before the game even begins. Long time fans however, would pick up the Quint connection without being told. Thus there is no reason to even mention it; the images speak for themselves.
Furthermore, a key point here is that nobody has seen the black Rockman yet, thus there are no characters around to mention the relation to Quint.
Rockman, who heard this news at Right's laboratory, took off to the scene despite being under maintenance.Rock only heard "the news." Which is that "a group of robots calling themselves the Dimensions attacked Symphony City", he's yet unaware that there is a robot that looks like Quint/Rockman on the scene.
At the same time, Wily saw the dark Rockman, and to ascertain the mystery he sends Forte to the city. Wily however, saw it. Wily being Wily would obviously know about the real Quint, and is thus immediately aware that this is not Quint he's dealing with; it is another Rockman. The narrator makes his point clear that Wily wants to ascertain a mystery, without having to involve Quint into the matter just yet.
Just who is this dark Rockman really?!Solely narrative. Newcomers would be in total mystery, and fans would falsely conclude Quint, until;
My name is Rockman Shadow! Without the narrative showing that Rock has spotted a resemblance to Quint, the dark Rockman says his name; flat out confirming to Rock that he's not dealing with Quint; in fact, he identifies himself as Rockman, Rockman's shadow to be precise. By saying that name he pulls it away from Quint, and toward Rockman himself.
Who the heck are you? How can it be you look just like me?Which carries one big theme of the game. That this robot is literally Rockman's shadow; that as Rock fights his power increases, that as he obtains weapons from the enemies he defeats, it becomes increasingly dangerous for him; he will become like Rockman Shadow.
Likewise, Forte is completely left in the dark, as he never even was around when Quint was. Forte has to figure out another mystery; why does this robot have a similar smell as himself? Which carries the other theme of robots made in Rockman's image which fight to become the strongest; an everlasting struggle of facing stronger and stronger enemies with no gratification which can only lead to self destruction.
NONE of that requires Quint to be openly mentioned in the intro story.
The name Quint does is only brought up later when they can add the explanation that he's a modified Rockman from the future in context to Shadow's origin, and in a way that Forte who wasn't around at the time, also gets to hear it. Bringing the story full circle and gradually informing newcomers what the longtime fans already knew from solely the images. For anybody not new to the series, you'd only be lampshading the obvious.
Which is one reason the WS story sucks.
I suppose you can't even appreciate the story for the fact that Wily was not the bad guy, and the themes it carried about fighting stronger adversaries till self destruction and becoming corrupted by the power one obtains from defeated enemies.
But what if it's the same design, only in a different art style, the way some people think MegaMan Zero's Zero is?
You should check out the epic flashback to World2/5 at the end of the game. Not even Rockman looks the same as Rockman Shadow apparently narrates flashbacks in a different sprite style.
ZERO-series doesn't work that way, though.