I believe due to the number of different language servers they initially had in EU, some of different server types were merged at the last round of server merge.
Cross server type transfers were also done back when apac servers launch.
So they have done it before.
Actually there is one type of server for each language, last I checked, which was after consolidation to mega servers.
9 servers in EU, so that point is valid in the sense they have never done it before.
It is invalid in the fact that 85% of the people want to merge anyway. PVP players don't mind because there isn't open world PVP going on now, so it can't get worse. And increasing the amount of players will increase the amount of WZ going on. I'm on Gav and 80% of the players do PVP (that number is a guesstimate, the 85% wanting to merge was from the survey)
The RP clique is least interested in moving, but even they will get more players to RP with, and more player intolerant of them getting harassed for RPing in an MMORP
G <- me being optimistic