Let me re-explain.
In the narrative of what was going on the character himself is significant. But at that very moment in the story telling all the show did was say "this isnt the doctor" followed by putting John Hurts name on screen.
That was it. Can you not see how someone who doesnt read the forums much before watching was just scratching their head like "wtf, yes thats the actor John Hurt, great, anddd??". You didnt see David Tennant get a big "David Tennant" right under him when he first appeared. You didnt see Matt Smith or anyone else get it. Just John Hurt. Why did the show feel the need at that moment to tell me the actors name? Especially when its going out of its way to tell me this person IS NOT the doctor, he's something else. What is he? Well according to the onscreen clues, he's John Hurt...
No, it's made clear he's an earlier incarnation of the Doctor, not a different character. Just someone who, for some (at the time) unknown reason wasn't deserving of the name 'Doctor', according to himself.
There was a lot going on in that scene: seeing glimpses of all the earlier Doctors, teasing the 50th anniversary (which was BIG at the time - there was simply no way of not being aware of that context when watching it when it aired in the UK given the media hype, and the biggest gossip for months at a time was 'which old Doctors will show up?' - how about one you haven't seen before?), the knowledge that Matt Smith was leaving soon, nobody knowing who the new Doctor was going to be, suddenly realizing there was a 'missing' incarnation of the Doctor in there and that's he's standing right there in front of us, his name and the little conversation instantly reminding viewers of the Time War between the classic and modern show...
I'm sorry it didn't click for you, but I always felt it was a terribly well put together scene, and possibly the best cliffhanger the show ever had outside of Hartnell dying and suddenly turning into a weird rejected member of the hobo Beatles. Honestly one of my favorite moments of the show.
Adding the words 'Introducing JOHN HURT as THE WAR DOCTOR' is simply a stylistic choice to hammer down the gravity of that moment. A big name A-list actor, playing an iconic part (joining a very, very limited list of actors who did so before), right before what was promised to be the biggest party in the show's history, with the media going crazy over it for months at that point).
If your complaint is that it requires a little knowledge of what the show is - well, sure. It's a season finale. Of a show in its 7th season (not counting the classic one). In a big fanwanky leadup to a fanwanky 50th anniversary party. They're allowed to use that stuff - it's like complaining what the big deal is about Force Awakens ending with Mark Hamill. You don't even need that much context really, all you need is a very basic understanding of the idea that multiple actors have played the part (which the episode hammers down by actually explicitly showing all of them multiple times, in a way never done before in the modern show). There was never a better place for going deep into that stuff than right before the big multi Doctor 50th festivities. And it's intentionally a tease for what's going to follow, although definitely not as baffling as you're painting it.
