But Ed Brubaker didn't reveal new information that we didn't have previously. He completely rebooted the entirety of Cap's continuity with his 2005 "Man Out of Time" story arc which led right into The Winter Soldier. Full disclosure I've been a Cap fan since the late 70's and own a comic collection that dates back to the 40's and trust me, if you were to sit down and just read Captain America from his debut in 1941 to today you would find that it is absolutely
not one continuous story.
There's at a minimum three different continuities, though Marvel likes to essentially trick new readers into thinking that there aren't. You've got 1941 Cap who was injected with a needle, never knew Peggy Carter and punched bad guys with a teenage Bucky until well into the 50's. You've got 1964 Cap who drank the serum from a test tube,
did know Peggy and did
not do battle in the 50's and was instead frozen in the ice moments after he watched Bucky die in an explosion in 1944. And then you've got 2005 Cap that said that Bucky was an adult badass in WWII and was captured by the Russians after only losing an arm. And don't even get me started on the (IMO) lame super "noir" setting that Brubaker thought Steve had to exist in with everything constantly being half covered in shadow and Cap brooding all over the place like he's Bruce freaking Wayne.
But then the MCU comes along and offers yet
another "Square One" reboot that ingeniously mines from
all three previous continuities and takes elements that were previously in conflict and seamlessly integrates them into one narrative for all new fans going forward and for any old fans willing to embrace it. As is usually the case it all comes down to execution.
As you might be able to detect from my statements above I do
not like the Brubaker stuff. He went on record in multiple interviews saying that before he wrote Cap he was always a Bucky fan and then lo and behold when he takes over the book Cap is
killed so that his pet character can pick up the shield. I called BS on that and to this day no longer own any of his books. If they do that with Dragonlance, ("Wizards of High Sorcery are dead! Long live the Warlocks!") then yeah I'll dismiss that too, lol.
But what I'm assuming they'll do will be closer to the MCU. Bring in Sorcerers, Warlocks, and Tieflings simply because they're cool and fun but only as options to exist side by side with what was previously established, not to upstage or replace.
And even going back to your original supposition that Marvel only "revealed information that we previously didn't know" well they can easily go that route with Warlocks or Tieflings. Like Taladas (surprise! here's a new continent) they can just say "hey, look over here, a brand new island covered in fog with an isolated people descended from fiends who get their magic from their infernal ancestors."
