I doubt they will merge the server, because there are only 3 servers with each ruleset. And much as some people may claim in the forums that all people on the PVP server are okay with merging to Dalborra, there will always be many who are silent and disagree. So I think them merging us is totally unlikely.
Fine then don't merge the servers but..... give people the option to transfer from the PVP / RP servers to PVE server if they wish. It has been done already when we were given the option to transfer from US servers to an APAC server of our choosing, there just happened to be more people on the PVE server after the transfers were complete and still are more activily playing.
Besides it would be in BW/EAs best interest to offer this to subscribed players (some may reactivate to take up offer) prior to F2P kicking in which i doubt will bring in any major numbers, maybe a few casual players coming to have a look, considering that JB HiFi is already selling the game for $13 - $14