How to spread population across realms

Hi. Looking at the realms' population, it seems like cataclysm and MoP realm are in problems.

I was thinking about it and came up with a solution for Cata and MoP.

- Add "Website achievements"

After a player earns an achievement, he would receive a gift (up to the discussion). This gift would provide him some benefits for the whole account.
Example:

- level at least one character on each realm (on Warmane). After achieving it, the player would receive maybe 1 month queue skip, 10k golds, 1 free donation item, etc...

- players would start to play on cata and mop just to get the gift for their main toon.

What about; I'm playing on Icecrown for example, downloading MoP/cata just to level 10 characters on different accounts > back to Icecrown with 100k free gold and delete MoP/cata forever. 1 month later Icecrown prices are 100% higher and new players complain.
If you want population then simply fix the ingame bugs.

I like your idea about Warmane's website achievement system. But probably it should take so much time to think about it to be good enough and not misused.
It doesn't need to be expansion-wide, some people just don't want to play that or that expansion. Like Remphan said. It would decrease a lot current economy if you take your rewards. Rewards doesn't need to be big but small and constant, psychological fact.
What they should do about Cata and MoP it's really complicated. Someone says it would be good to advertise again on "top100wowservers" and so on...
Someone says they should merge them. Someone says "just fix the ******* server and people will come..." Let leave that to Warmane. What they really need to do is to keep focusing on TBC and WotLK servers.