Not a measure of success of a VFS, a measure of success of a MP server that is meant to be enjoyed by people as much as possible to expand the community. Of course that is one squad's objective, and we know others, such as yourself have other goals. Like highly detailed co-op with no shmucks around to mess it up.
I am going to kick myself in the ass for agreeing with Kuky, but I said the same thing as Kuky (now I am kicking my ass lol). Yes, you can fight PvP in A-10, but it is not designed for A2A and is severely limited in that regard. Real PvP will be with Fighter Jets, and as MoGas stated, you want to encourage friendly competition and a strong player base with PvP. I am fairly confident, once we have DCS:Fighter, the number of unlocked servers will increase.
In the end though there are pros and cons for locking servers. We all have our preferences.