Like all game implementation or improvements, it is used to try to increase the overall traffic and/or keep the consistency of its gameplay. No developer would want his/her competitor to take away from its fan base. This can have a negative or positive effect depending on each individuals preference. As for server linking, there are benefits but also consequences.
As for the benefits of linking, it includes a larger population base for WvW players, for most servers, if not all. This allows a larger time spectrum for groups when you log in for fun and/or want to accomplish objective within WvW. These include more enemies to fight, players that can help, and meeting new players to kill or befriend.
For the consequences, these include not being able to easily join WvW gameplay whenever you wanted to due to high queue during primetime and reset time, especially when players usually hardly had a queue before link. Bad reception from other servers caused by some of its players. No recognition of home server for the smaller servers. Larger population means larger coverage for your enemies that could deny all small guilds from doing anything unless they merge two guilds together. Being thrown around like a hot potato until they determine their next step for WvW.
Unfortunately, there is no right or wrong answer to this linking “problem”. With server linking, most likely it has brought in new players due to higher level of activity for those that are playing or have just started playing. But this also caused problems for those in a community.
For me, a community is a place where you feel like you belong and have fun. It can be a server or a guild as it is the people you interact with that makes it worth a while to stay. The server I am on, Ferguson Crossing, had fun time doing server activities on certain days which is why a lot of us do not like the server linking as at times, we would even queue a map just to play around as a lone server.
Though I would personally would like to go back to the old days before linking, I have to say that even if it did change back, it will NOT be the same as before. People have acquired the taste of linking and quite a few people like it. This in turn will damage the current gameplay/community and fan base if it once more turn back to lone servers.
So, in the end, the linking has already happened and any changes will have side effects. If people can actually get enough support for lone server then that would be great which mean people enjoyed the old system more than linking. If they do not change linking then they should at least have a more stable linking to create interaction and community with different servers. They should also see if people want our own server names when enemy sees our name tag so they have a sense of rivalry/impression of that server.
Now we wait and see.