First off, the wowhead upgrade links are your killer feature that brings me here instead of be.imba. They link the armory's search, which, well, blows.
So now, recently wowhead added the nifty feature of sortable columns listing the stats you filtered on. Now I'm sure the basic stats already work fine for this, but as a healy priest my upgrade links use the "Healing item" filter, which gets no column. Here is an example. Now, if you were to also include conditions for the other stats I would care about so they can be sorted against, that would rock! This is simple to do, just add a ">= 0" filter for the stats in question. Here is the same search, but with the added columns.
Since wowhead.com initiated the built-in weighting system it might be easiest to use the pre-fabricated ones. Grab the current spec and have it querry wowhead using those pre-defined factors. So instead of what you made up for it wowhead would give you this Weighted Result.
Edit: The only times where this may become a problem is when wowhead has multiple prefabricated specs for different talents. I.E. feral druids get "Fearal Tank" and "Feral DPS" on wowhead.