I like the way you worked it into his armor, rather than into his body. Making it less of a physical augment and more of an ability augment. This removes a major drawback, which I'm glad nobody ever acted upon, and at the same time removes a major boost that it grants. 

The drawback being the distinct vulnerability to electrical attacks, and the boost being the obvious strength and speed boost. 

It's interesting, and I do like how it's done.

[b]Edit:[/b] The Word Engine itself causes a vulnerability to electricity because organs are encased or infested with metal, including the heart. A sharp electrical pulse would cause near instant cardiac arrest. So having it outside of the body, rather than inside, is an effective way to bypass this.

[b]Edit 2:[/b] The Word Engine MK. 3 bypasses this in a separate way, by being integrated into a suit with a non-conductive casing.