I think the thing that is being overlooked is that instancing in the emulator is just 1 more feature that can be used by admins to make cool new things. Anything that adds more options and variety to the emulator is a good thing. Sure, instancing every zone isn't really a good idea in the emulator, but having the option to do so is nice. I can already imagine a couple of great reasons to have instancing in the emu. One would be for end zones that are overpopulated. On custom servers, quality content takes a while to create, so some zones may be too over-saturated with players. Not only does this cause way too much competition between players, but it can also cause performance issues. At least on my server, if there are more than 20 players all raiding a zone at once, it risks a zone crash. I have seen as many as 30 in a zone, but it crashed after a short time. With instancing, you could set a cap on the zones for how many people can be in them (in the zones table) and then create new instances where needed. Another use for instancing would be for zones that are designed for a max number of 1 to 6 players or so. If a raid would trivialize the content, then you might use this type of limiting. With instancing, you could potentially still allow others to play in that zone without having to wait in line for the people currently in there to leave.
I am actually working on a new player limited and time limited zone access script for a zone on my server. I will post it in the custom section when it is all done. I don't plan to use instancing for it just yet, but it is really cool to know that the option is there. I don't think instancing should be used as widely as it was in EQ2 or anything, but I do think it will be a nice option to the emulator. And, I love having options
Oh, and I quit live around that same era. Though, my reason for quiting was due to almost all of the best guildies I had played with for years were gone. Also, I didn't like the fact that I had to work my ass off for like 10 hours every day for maybe 2 or 3 pieces of loot per month. Progression that slow is just ridiculous. And just when you start to get caught up to where you feel uber again, they release another expansion and make all of your hard earned gear obsolete.