This sounds like a really good idea, and it sounds like it is being implemented well. Kudos.
I wondering about crossing this (or the Guild Wars skill templates) with a standard mod sharing interface. You would open up a menu of builds in use, possibly player-built but why not just automatically pull the data on what is in use? Is there some sane way to show the central tendency of other players? You would not want specially named builds, and perhaps souls provide too much granularity for an effective display. Perhaps something like X is the most popular skill/soul/whatever, 30% of players choose combination ABC as three of their GW2 warrior skills, etc. I would also want some index beyond popularity, say xp earned or kills using that build, to keep people from intentionally messing with stats by, say, making Uber Warrior Build as a main then filling every slot on every other server with a level 1 using a crap build. I don’t know if enough people would do that to seriously throw off stats, but I can see the effort being made to break any game system.