Incentives for moving Data Center

[YumieYumiki]

I will preempt this with:
I know congestion should not be this bad to begin with given the player number drop.

I don't think congestion has anything to to with the global number of players, it has to do with people all going to the same data center simply because being on a more populated server is advantageous (lower prices on MB, faster queues, etc.)

Any expectation that people will act against their self interest for the "sake of the greater good" (like improving server population balance) is completely unrealistic in a MMORPG.

Therefore regarding your other point: moving to a different server should at a minimum be completely seamless and hassle free, even for people with houses, to the fullest possible extent. No fussing around with retainers to keep furniture, for example. I'd go as far as to say that after moving you should be able to bid for free on an available plot and your house should be entirely restored with all its furniture if you win the plot.

And even that wouldn't be enough for people to migrate to less populated servers, because even if the process was completely smooth and hassle free, doing so would still work against their self interest. You'd have to give incentives on top of all that. Perhaps give them the favored server exp buff, with the same rules as when creating a new character (ie it works only if you play on that server).