Well that is one of factors , those games sux so much that they haven`t got even 10k of unique players each month.
I agree with an oceanic server, ping always matters don't let anyone tell you different, you either have it or you don't - which is why we suffer in MMO population because there's little to none mainstream MMOs that support AUS gamers.
Oceanic servers help keep people that speak the same languages together too, more interaction between players on a region specific server. Nothing like joining a group of people to have some fun then find out your the only one who does not speak German fluently.
200-500 milliseconds of lag is the difference between life and death in PvP. Look at the horrible lag Space Marine multi-player suffered because of P2P match-making. It ruined the experience completely. I guess if we're all connecting to the same mega-server it shouldn't be too much of an issue, but it'll still benefit those who have less ping than others. Anything more than 200ms to server and it'll be a noticeable handicap.
Any lag in PvP is a matter of life or death especially in games that implement the 'Global Cooldown' mechanic. A super server is a great idea, but its not practical. However for any instanced content then a cross server queue system would be a good idea to reduce queue times.
If you are going to do this, can you at least lock chat by language? It does get fairly annoying when the chat box fills with a language you can't understand, and 10 different languages are all competing for the same small chat box. Also, if it happens to be one person who speaks a language that few people on at the time do, and they are asking a question, there is a much better chance they'll get help if it hovers in the chat box for those people who do speak their language.