I think this may have been a case of that specific sword simply having wildly inflated secondaries. If I recall correctly, when I played during Wrath, +STR and +Hit were the stat kings for plate DPS classes (I remember all the guides recommending +STR gems in every slot and +STR enchants on everything) and secondary stats were, well, secondary, and inflated secondaries on a weapon weren't that big a deal. But now that secondary stats have so much more importance, I suspect that an "outlier" weapon like that just wreaks havoc with modern calculations, so that all the addon sees is that this particular sword offers +15 more Haste and Crit than everything else that drops.
I love this addon and the accompanying standalone tool. Thanks so much. In particular, I enjoy the commented section including bagged items so that I can easily simulate comparisons w/ the copy= command. Is there any way to include bagged relics for comparison as well? The addon must have access to the identifiers, and it would be MUCH easier than trying to match them on Wowhead.