I've wanted to combine Great Critical Charge, Deep Wounds 3/3, and Limb Splitter 3/3 for a seriously damaging Critical Charge. Not even sure if axes get the Crit boost with Limb Splitter or if it's just sword specific. I've also wanted to use Wuuthrad w/Elemental Fury ;p

Almost 100% certain it's sword-specific. But hey, every race has the Imperial Luck racial perk so who really knows.

Right. It'd be easy to test. Just perk Critical Charge and perform it with a Battleaxe on an enemy. Reload and perk Limbsplitter 3/3 and Critical Charge and if the same axe does more damage then it works. I might do this tomorrow and see what's up. I hope you're wrong but a part of me knows your right :,(

physical damage I believe, to be more specific. 

Right - so poisons and on-weapon enchantments wouldn't be factored in, but I think potions of Fortify 2-handed (and Fortify Marksman?), along with enchantments of the same, would factor into the 1.2x damage vs. elves. 

Not sure about critical damage, though... of course, critical damage could only be achieved via Great Critical Charge and would be probably in the area of 12.5 points of damage (base damage for Wuuthrad is 25, I believe).

If you test this, please let us know!

fortify potions are added as a multiplier after damage is calculated so they should be boosted just fine.

YES! This is amazing, i was actually considering doing a monk class on legendary using this but didn't have the stats and hadn't tought it through as much as you did and figured it wouldn't be viable.
This will certainly help my no-crafting legendary character hurry up a bit lol, but it does not work for magical damage right? going to have to figure something out there, multiple people on the internet told me it boosted ALL damage, so i was happy with the fact destruction magic wouldn't be so damn slow on legendary, but ohh well, i have my frenzy i guess... And as soon as i'll have all 3 words, i might just give unarmed a try! a problem i have though is that the animations of unarmed don't strike me as a monk, but rather some drunk nord..
I realize, not being a khajit and not really planning to wear any unarmed gear, it will take a while before unarmed damage becomes even noticable.. But this is definitelly something that allows for even more out of the box builds! I'm also glad you clarifies this not being a glitch, i just can't stand using them personally.

''For bonus marks I even gave a go to using telekinesis and a cabbage to assassinate someone.''
Now this is what i mean by an out of the box build! ''The Cabbmage''

Anyways, this opens up alot of options! Thanks for doing the research for me! Much apreciated

I wish it worked for destruction but that would probably have been slightly overpowered!

Very informative read. Ive always wondered how this shout really worked. Now I know and now im going to hunt down the 3 words for this shout a bring down a rain of havoc upon skyrim.