All classes to 100. Check. Currently playing Final Fantasy XIV. Homogenization is extreme, but classes are still fun.
My opinions: 5.0 was the golden age of content, the pruning was far too light and HFC is the final raid of WoD.
I am not touching the PvP realm issue but multi-character transfers are another topic altogether. It doesn't seem like an unreasonable suggestion for the players to be able to transfer a notable number of characters at once for a somewhat discounted price.
There are risks with the biggest ones being tied to individual realm economies but as long as the service is designed appropriately with smart limitations then I think the pros outweight the cons.