With some mods, like Third Age: Total War (turn it into LotR) or Broken Crescent (focus it around the Middle East rather than Europe), it's pretty obvious what the "big idea" of the mods are. However, with others, I don't quite know where to start. When I try to answer a question like "what are the pros and cons of Stainless Steel, Darthmod, Lands to Conquer, Deus Lo Vult, HRR, and The Long Road," I find myself in an endless list of minor features: this mod adds dismounted mailed knights, that mod gives the Byzantines more gunpowder units and gives them Greek flamethrowers, etc. If I find a summary page on Stainless Steel or something, it won't be an overview of SS as a whole, but rather just what's changed between Stainless Steel 6.0 and Stainless Steel 6.1 or something.
Basically, what I'd like would be to find a site which basically reviews the mods and summarizes their main objectives, and how well they achieve those objectives, in about a page per mod or so.