I'm failing to see how merging will make it better for the majority. Bear with me here.
I'm from UK. I speak english only. Therefore I've been playing US servers because its pointless attempting to team with french/spanish etc because we can't understand each other. No matter how skilled the team is, communication is vital to good team work. Therefore, there goes the teamwork, we all die.
Now for the majority of people, having language-separated districts is good. Someone who can only speak french goes to the french district. Someone who only speaks italian goes to the italian one. They can join a group of people that can all understand each other.
It should make no difference numbers-wise... say there are 5 districts. And say there are 5 languages. Also say there are 1000 people on european servers. Now this means that before, you would have 200 people in each district, but all speaking 5 languages. So in each district you would effectivly have 40 people speaking english, 40 italian, 40 spanish, 40 french and 40 german. So ignoring those who can speak more than one language, you had 39 other people to group with. Now however, you go to a district with 200 people on... and all the other 199 can understand you.
If you have people on your friends list, well youc an still message them and meet up with them in another district. And I get your point about joining up with spanish/french/whatever and all speaking english so you can understand each other... but you can still do it. Maybe you should learn spanish so you can go talk to the spanish in their own tongue. After all, everyone in europe is expected to learn english, but us english (yes you said you're not english, im talking about me

) never attempt to learn another language so that, say, germans can talk to us in their own tongue.
UK people will come back from US servers... I sure as hell don't wanna help the US win the favour of the gods! We do too much of that in the real world!