I remember when I was a Halo2 fanatic. On the extremely rare (two occasions) that my 4 man Slayer team was matched up against Japanese players we found ourselves playing against completely unexpected and unorthodox strategies compared to strategies employed by the NAs (and EUs). It was a little refreshing. I feel like NA and JP player bases are able to learn from one another on mixed servers and that, IMO, just helps the evolution of all things.
Aegis has a very large Japanese population and I enjoy it. My friends and I hit our first lvl 50 battle class (shortly after launch) with a Japanese player and each of us (us and him) still remember it and throw each other the daily emote. Now we're not just a gimpy lvl 50s in vintage haubs but decked out in Darklight and on the cutting edge of endgame content and I think it's rather cool that, despite speaking different languages and being in what will one day be open world rival linkshells, we both have that memory. I communicate periodically with Japanese players (thanks to online translators) about things related to the game, fights, progress, etc. I have a lighthearted emote feud going on with a JP Lalafell named Shan Totto that has been going on for over a year. I don't think these things diminish my game-world; I think they add to it.
If 2.0 is the success we hope it is and there is a population boom as a result I don't think you'll be as bothered by this.
It's not that your desire for segregated servers are absurd. Were they segregated originally (in XI and with XIV) and it was what I was used to, I don't see myself thinking `man, we need a bunch of people who don't speak my language and have a completely different mindset and culture than I do on this server!`, but having gotten used to it (since XI) I enjoy playing on a diverse world from people all over the planet. The internet is cool (*'-')b