I know bartender let's you change with specs I think. But the one who recommended an alternative add-on is probably the best option. It is possible to find the keybind file in wow, copy it and paste it on your desktop. Then you can just drag them into and out from the file to WOW TBC Classic Gold edit the settings.
My primary concern is the client's and the global interest . The 3.X client is superior because the engine is much more refined as well as the tools are less complicated to use. However, I feel I have lost the vanilla aspects of changing from 2.X to 3.X.X. I do not want to offer WOTLK content. Also, I'm not sure who would be interested to play on the 2.4.3 server.
There are a lot of custom servers being launched and the volume never increases. I believe that they launch with very little information. I am confident that a server would launch when it announced its existence after putting in the work.
3.3.5 emulators are not less when it comes to quality , compared to 1.12.1 emulators. I don't know where you have this information from. Trinitycore has 34k commits, as opposed to 4,8k for Vmangos. TrinityCore has a lot more features that are stable and performance, and you can access tons of applications that aren't accessible in 1.12.1 emulators.
VMaNGOS its strength is the fact that it has work to cheap Burning Crusade Classic Gold put into while it is used for Nostalrius as well as Light's Hope. There are plenty of problems of instabilities, bugs, exploits and similar hard-to-foresee stuff that only becomes apparent on high populace servers. This is VMaNGOS strengths. It's very scalable, due to its main use case has been high-pop vanilla servers. It does one thing well and very well as vanilla. Darrowshire is a perfect example of this.Recently they also added an implementation of the Warden anticheat