I don't have a better tool, per se, though maybe I can help with the tools you already have.
In Recount, flip to the "Damage Taken" list (actually any page will do), and click your name. That will bring up a sub-window with info depending on the tab you clicked from. At the top of the new window created there is a small magnifying glass. Clicking that will switch the window to a different sheet format. The new window will show outgoing damage enumerated in terms of damage type and all the smaller breakdowns. If you click the bottom half of the window (there will be a note to tell you you can do this), it will switch to the breakdown of damage taken. I believe this shows avg hit size taken, and it will show how your dodge/parry/block breaks down, as well as the varying damage types. Note, this list also distinguishes between Melee (mob/boss's main target auto-attacks) and physical damage (Patchy's hatefuls, physical bleeds and impales, etc.). Hopefully that will give you more of what you're looking for.
Alternately, WoW has a handy feature built in: you can create combat logs. These are essentially transcripts of the combat log in a text file. To start and stop logging type "/combatlog" in your chat line. When the feature is on it will store the data in a text file in your WoW directory in the subfolder "Logs." This file itself is pretty hard to read nowadays with the advanced combat log available in game, but at the same time the data has become MUCH much richer and more specific. The best way to get a clear presentation of the data is to go to WoW Web Stats (WWS) and create an account. It's free and will store your logs for a couple weeks without any upgrades. There is a Java-driven client that you can open. You need to be logged out of the game, and I'd recommend renaming the combat log, moving it, or both, if you don't future logs will just be appended to the old one. The WWS applet will ask you browse to your combat log and enter some simple comments. Once you hit 'ok' it will take all the data and organize it into a very useful breakdown of everything that happened, damage done, damage taken, and healing done, enumerated by every swing, cast, and detail in your combat log. It has a lot of handy tools, especially as a tank, for what data it shows. I know this will tell you specifics of exact hit size, and it is easy to view specific fights, or even just isolate trash info.
Hope some of this gets you what you're looking for. If anyone else has a more specific tank data tracker, I'd love to hear about it.