Well, it wouldn't be too hard to keep them different enough to not be a "Rip off"
For example, because FFXIV isn't an isometric turn based RPG, you wouldn't be flinging your target like 30ft into the air and slamming them down (Or other such fancy things that get done in Disgaea...)
Not to mention that Upheaval already gives us precedent for fissures exploding.
(Also, the next skill in the video
Violent Storm is not too dissimilar to
Storm's Path 
)
That and really, my suggestion is more just adding a little bit more to the current animation. Following through with the "Inner Beast" strike, into a jump and slam down. But with a bunch of cool particle effects so the signature "Big Bad Tank Move" actually looks as visually impressive as its potency. (Rather than being nigh indistinguishable from the bog standard level 35 skill we've had for years - To the point where after the Job Actions trailer, many people thought that they were just showing off the new slightly updated Inner Beast animation and were saving our big bad signature move for later to let the other tanks get some hype...)