It's more of a rhetorical question. Basically what I'm saying is: these devs are working hard on this server, harder than any private server I've ever seen. Seeing how well they scripted the AI is so impressive. Since we already know that this server is going to be possibly the best private server ever made, the main issue that should be focused on is the playerbase. The quality of the server almost certainly wont be in question, so population is what will make or break this experience.
All this server can do is look at past servers and see why they failed...and try to not repeat the other server's mistakes. There have been a few decent servers that have gone down hill for various reasons.
- This Server will have a decent layer of DDoS Protections
- Kronos is labelled as an international server, so the primary language is Englsih
- From what we can see so far, quest and dungeons bugs will be near non-existent
- Kronos has an anti-cheat system
- Is part of the twinstar project - so whatever the case maybe there will be experienced devs working behind the scenes
- The server is located in Europe - reduces likelihood that Blizzard can slap across a lawsuit
This project is known...and for better or worse...has been advertised all over the place either spammingly or methodically (I suggest anyone from refraining to personally advertise this server). This server does enough of its own advertisement to grab the attention of players.
All that can happen now is to wait and see. Enough people know about this server, when it goes live, word of mouth will start to bring more players in...especially when is has been confirmed that any aforementioned bugs don't exist...it might take a good month or two for Kronos to have a decent recurring peak in population.
Moreover, remember that there are many different types of Vanilla players. Some just want to play on and insta 60 server, others might want something Kronos does not offer. Nonetheless I think it is safe to say that there are plenty of people who want to experience x1 blizzlike vanilla.
Also to note, there are a few other -stable- x1 vanilla servers about...or soon will be. Each with their own community which will ultimately split the potential player base a little. Which is not a bad thing...I find the more decent private servers available, the better the vanilla community as a whole will be...because ultimately more servers (of a different kind) bring more people in.
TL;DR - Who knows? I would like to think when the server opens there is a minimum population of around 200-300 odd (horde and alliance) with peaks up to 700-1k...to then, in a few months time, a constant population of 400-500...my estimate anyway