In short it is a clone of classic D&D. And Old School Renaissance will treat it as such. Mainly because it's adventures and settings promises to be compatible with the editions we do like and play. Promises to compatible to a far greater degree than 3.X, Pathfinder or 4.0 ever did.
Just look at the Cave of Chaos adventure. Despite the differences in mechanics it works out about the same way you expect if you ran it with Mentzer rules.
I created my own original adventure to use for the playtest and did everything the same I would preparing for Swords & Wizardry. And having run it 2 and a half times with three different groups it was nothing like the 3.5/4e games I played and a lot like the Swords & Wizardry/Majestic Wilderlands hybrid I use for my regular campaigns.
The playtest is a clone and the Old School Renaissance will treat it as such.
No more and no less.
Ist success among the OSR will be the same as any similar high production value project. If it open to third party support, plays nice with the community, and produces good material using the format we had seen then it will have a slice of the OSR as customers.
However what it will not do is supplant the love or the playing the classic editions. Because what newcomers forget time and time again is that the point is not to play something like the older editions but the older editions themselves. If you want to get customers among the OSR then your work needs to be useful to people playing and refereeing the older editions.
I am optimistic at this point mainly because of the format of the included Cave of Chaos, the fact it works as is in actual play and that it is the full caves and not some stripped down version
I see by the comments I didn't get my point across. The Cave of Chaos adventure is almost as verbatim copy of the original and it uses ONE line stats blocks that are useful in actual play. If this format continues to be used this means that it is highly likely that D&D Adventures, Settings, and maybe supplements would be of some use to the OSR. Much in the same way that Swords and Wizardry gamers find material useful that was written for OSRIC.