Aye I have been hearing the buz of Vangard as well. I will most definately be taking a look at it.
No,

the visionary from Horizons was David Allen.
If you goto pc.ign.com, select the pc game horizons, and click the news link, it will take you back as far as when David gets "fired", pretty much.
The visionary for Vangard would be Brad McQuade =)
Brad McQuade was EverQuest 1!
Back in the day, a man named Brad, runing a company called Verrant, was designing a new kind of game. It was to be a mud/mush, but it would do so much more. It was going to have graphics in it.
It would be a 3D representation of a MUD (Multi User Dungeon; all text based and no pictures). To finally see inside the world rather than just imagining it.
Supprisingly enough, when EQ1 was coming out, it was frowned down upon by those MUD communities because they believed constraining a MUD to just 1 man's vision went against the grain...
...how unbeknowing to them all that it would come upon the earth as a plague would; an addiction far worse than crack.
Ok, back to the story...
I believe Brad contacted Sony for assistance in getting the game out the door, on the shelves, and supported on the servers.
Sony, not really taking it seriously, but not wanting to completey disregard a new concept like this, brought Verrant in under their sports title, 989Studios... yeah... cause when I think EQ... I think John Maddan football :P
And then EQ came out... and it was BIG! It was the new wheel, telephone, lightbulb... it was the new "big thing"
Now the rest of the stories a bit fuzzy...
I think, since Sony pretty much owned all the servers, and the internet connetion lines, and support staff; that after the first year, Verrant was flat out purchased by Sony (honestly, I dont think Verrant even had a choice, lol).
But! It was made clear within the contract, that Brad woud hold custody of all developement rights... was Brad's "vision" after all.
However, it only took Sony 5 years before they even muscled him out of that role.
Brad quit from Sony Online Entertainment in good standing. Matter of fact, thats what they were pushing on the media more than anything... "no hard feelings".
It is my opinion that Brad quit Sony because they kept messing with how he wanted the world ran and undermining all his projects with crappy ideas.
Well, now Brad's back again... whole new company... whole new bag of tricks... 8 years under his belt to get this new company's foundation bolted down, get the game designed and coded. Get the ingame content all written out...
what? I never said he quit Sony and was a poor broke beggar

I am sure they payed him off well.
And your question still stands, Flint... will he be able to pull off another great visionary success? Or will our bloated MMO market just kick it to the curb like so many games lately.
I think Brads feeling pretty lucky, now that EverQuest2 has been considered a disapointment to the gaming community as a whole. I am glad Brad got to see Sony eat Crow, as it were.
Oh, another note... and this ones important in my opinion...
Brad went to Sony for help again... They are to help dristribute the game, and to provide billing and account management. Sony will also be managing all the hardware. But Sigil will be providing all ingame and out of game support. - THANK GOD!!