Martial Elemental Arts is a plug-in for Sledgehammer that adds personal elements, elementally-flavored attacks, and weapon degradation.
The PDF is a single page and it mirrors the format and aesthetics of Sledgehammer really well. The font is very slightly difficult to read, but there's also helpful graphics and everything in the text is explained clearly.
You *do* need to roll additional element dice (which are used by WuDe) as part of this supplement, but you can easily sub in a d6 and just assign each facing its own element.
Mechanically, there's nothing in Elemental Arts that really shifts the balance of Sledgehammer towards the PCs.
Elements add description to attacks, but rolling 6s on your element die gives you corruption and can eventually destroy your weapon.
Overall, I think if you want to play an elemental warrior in Sledgehammer, this gives you the tools you need to do that. And if you want a resource of prompts that will help you flavor your melee attacks, I think Martial Elemental Arts is just as useful for DnD or any other fantasy melee combat game.
Using it *will* make your Sledgehammer gameplay slightly tougher, and taking a moment to describe how your attack is drilling or crushing after every attack may cause your language resources to start to run a little bit dry, but I think Martial Elemental Arts can be tweaked a little bit to resolve both of those issues. Making whether or not you attack with elemental energy a player choice, and having those attacks deal +1 damage if you roll your element could keep the game balance more neutral and let players opt in and out of their elemental powers.