Your points are extremely weak, OP.
1) Server instability is an unknown factor. Old server could be unstable too, with returning players + some new.
2) Fresh server will only get more and more popular, since the leveling will become
easier as time goes on, say week two or three, if not sooner. The fresh new levelers currently have no reason to roll on the old server, except for those who want AQ and Naxx. And these vanilla veterans are already on the old server.
3) Fatigue? We're talking about new players and them not joining an old server with geared people.
4) Lack of AV did not stop the old server from becoming popular prior to AV release, so this is another weak point. AV is just a small boon, doesn't make or break content. I have never heard of someone suggest going on K1 over K2 cuz AV was out, never.
5) This is obvious, people like their old chars, but again for new players joining this is not applicable.
PvP scene will slowly degrade away as max level folks have already finished ranking. Without enough new players to keep the PvP population pool big, the bracket caps will be more limited, fewer rank points. Progressively getting worse for puggers and rankers alike.
PvE scene will be filled with recruitment messages as older guilds will struggle to fill their members who've quit, lacking new 60s to fill the gaps. This problem has
already begun
prelaunch as guilds struggle to unite their old members.
The above has been
proved already in the private server scene. K1 have been crying for a merge even before the Nost relaunch announcement. The old server getting into war effort stage has nothing to offer a green playerbase over a server that, like them, is completely green.
The only possible solutions I can think of:-
- Launch the fresh server at the same progression state as the Old PvP server. So new players have a choice if they want to join existing guilds on old server or form new teams with undergeared people with a slow starting raiding scene. This will make management of the servers much easier, as patching will be in the exact same stage, including bug and item fixes.
- Pre-announce TBC exclusively first on the old server. So TBC lovers can level and keep the leveling scene alive while waiting for the TBC swap. This might be useless if another project releases a good TBC. (kek) Anyway, I doubt any significant progress has gone into making that possibility real.
- Release old servers (PvP and PvE) a significant amount of time before the fresh server, forcing new lifeblood to level (or continue leveling) to max level on the old server and join struggling guilds who are all going to be massively recruiting people, to replace lost raiders. This is a band-aid fix. Once the fresh realm is up the problem of lack of levelers will return.
- Have no queue on the old server, but cap the fresh server to limit flow of new players into the fresh realm. Unpopular option, but you can disguise this as a "management issue" or some political term.
In conclusion, without a proper method of protecting the original PvP server from going through a new player drought before the release of the fresh realm WILL cause the older server to suffer and degrade to the point of players just raid logging or straight up quitting for newer prospects across the horizon.